Difference between revisions of "Synapse"
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+ | {{Synapse}} | ||
+ | |||
Synapse provides an easy to use serial port and synchronous TCP/IP library. | Synapse provides an easy to use serial port and synchronous TCP/IP library. | ||
__TOC__ | __TOC__ | ||
− | |||
− | =Overview= | + | == Overview == |
− | Synapse offers serial port and TCP/IP connectivity. It differs from other libraries that you only require to add some Synapse Pascal source code files to your code; no need for installing packages etc. The only exception is that you will need an external crypto library if you want to use encryption such as SSL/TLS/SSH. | + | |
+ | Synapse offers [[Hardware_Access#Synaser|serial]] port and TCP/IP connectivity. It differs from other libraries that you only require to add some Synapse Pascal source code files to your code; no need for installing packages etc. The only exception is that you will need an external crypto library if you want to use encryption such as SSL/TLS/SSH. | ||
See the documentation on the official site (link below) for more details. | See the documentation on the official site (link below) for more details. | ||
− | =Installation= | + | == Installation == |
+ | |||
Installation can be as simple as simply copying over all files to your application directory and adding the relevant Synapse units to your ''uses'' clause. | Installation can be as simple as simply copying over all files to your application directory and adding the relevant Synapse units to your ''uses'' clause. | ||
− | Synapse download/ | + | A more elegant and recommended way is compiling the laz_synapse.lpk package so you can use the same units in all your projects. |
+ | |||
+ | Synapse download / Wiki info page: [https://github.com/geby/synapse Download and Wiki] | ||
− | =SSL/TLS support= | + | == Support and bug reporting == |
+ | |||
+ | The Synapse project has a mailing list where support is given and patches can be submitted. | ||
+ | |||
+ | Bug reports can also be mailed to the mailing list. | ||
+ | |||
+ | See the [http://www.ararat.cz/synapse/doku.php/support Synapse support page] and some well presented [http://synapse.ararat.cz/doc/help/ on line help] | ||
+ | |||
+ | == SSL/TLS support == | ||
You can use OpenSSL, CryptLib, StreamSecII or OpenStreamSecII SSL support with Synapse. By default, no SSL support is used. | You can use OpenSSL, CryptLib, StreamSecII or OpenStreamSecII SSL support with Synapse. By default, no SSL support is used. | ||
− | The support is activated by putting the chosen unit name in the uses section in your project. You also have to put the binary library file in your project path (Windows), or install it into your library search path (Linux, | + | The support is activated by putting the chosen unit name in the uses section in your project. You also have to put the binary library file in your project path (Windows), or install it into your library search path (Linux, macOS, FreeBSD). |
Synapse loads SSL library files in runtime as dynamic libraries. | Synapse loads SSL library files in runtime as dynamic libraries. | ||
− | * For detailed information refer to [http://www.ararat.cz/synapse/doku.php/public:howto:sslplugin | + | * For detailed information refer to [http://www.ararat.cz/synapse/doku.php/public:howto:sslplugin SSL/TLS Plugin Architecture] |
* Some crypt libraries can be obtained from: http://synapse.ararat.cz/files/crypt/ | * Some crypt libraries can be obtained from: http://synapse.ararat.cz/files/crypt/ | ||
− | ==Missing library== | + | === Missing library === |
On Linux you need to make sure the required dynamic library is present/installed on your system. In case of cryptlib if the library is not present on the system, an error message appears during linking: | On Linux you need to make sure the required dynamic library is present/installed on your system. In case of cryptlib if the library is not present on the system, an error message appears during linking: | ||
− | + | /usr/bin/ld: cannot find -lcl | |
A similar message will be displayed when using other dynamic libraries. | A similar message will be displayed when using other dynamic libraries. | ||
− | =Web server example= | + | == Web server example == |
− | |||
− | + | See the [[Networking#Webserver example|Webserver example]]. | |
− | |||
− | + | == QOTD server query example == | |
− | + | See the [[QOTD|Quote of the Day server query example]]. | |
− | + | ||
− | + | == Sending email == | |
− | + | Refer to the [[Synapse - Email Examples]] article. | |
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− | |||
− | == | + | == Downloading files == |
− | |||
− | |||
− | = | + | === From an FTP server === |
− | |||
Given an URL and a (path and) file name, this will download it from an FTP server. | Given an URL and a (path and) file name, this will download it from an FTP server. | ||
It's mostly a wrapper around the Synapse code meant to make downloading easier when handling arbitrary files. | It's mostly a wrapper around the Synapse code meant to make downloading easier when handling arbitrary files. | ||
− | If you know exactly what you're going to download where, just a call to Synapse | + | If you know exactly what you're going to download where, just a call to Synapse: |
− | <syntaxhighlight> | + | |
+ | <syntaxhighlight lang="pascal"> | ||
FtpGetFile | FtpGetFile | ||
</syntaxhighlight> | </syntaxhighlight> | ||
+ | |||
will get you very far. | will get you very far. | ||
− | <syntaxhighlight> | + | <syntaxhighlight lang="pascal"> |
function DownloadFTP(URL, TargetFile: string): boolean; | function DownloadFTP(URL, TargetFile: string): boolean; | ||
const | const | ||
Line 128: | Line 104: | ||
</syntaxhighlight> | </syntaxhighlight> | ||
− | == From an HTTP server == | + | Example to get list of files in given path |
+ | |||
+ | <syntaxhighlight lang="pascal"> | ||
+ | //Use ftpsend unit | ||
+ | |||
+ | function FtpGetDir(const IP, Port, Path, User, Pass: string; DirList: TStringList): Boolean; | ||
+ | var | ||
+ | i: Integer; | ||
+ | s: string; | ||
+ | begin | ||
+ | Result := False; | ||
+ | with TFTPSend.Create do | ||
+ | try | ||
+ | Username := User; | ||
+ | Password := Pass; | ||
+ | TargetHost := IP; | ||
+ | TargetPort := Port; | ||
+ | if not Login then | ||
+ | Exit; | ||
+ | Result := List(Path, False); | ||
+ | for i := 0 to FtpList.Count -1 do | ||
+ | begin | ||
+ | s := FTPList[i].FileName; | ||
+ | DirList.Add(s); | ||
+ | end; | ||
+ | Logout; | ||
+ | finally | ||
+ | Free; | ||
+ | end; | ||
+ | end; | ||
+ | </syntaxhighlight> | ||
+ | |||
+ | === From an HTTP server === | ||
+ | |||
Given an URL and a (path and) file name, this will download it from an HTTP server. | Given an URL and a (path and) file name, this will download it from an HTTP server. | ||
Note that this code checks the HTTP status code (like 200, 404) to see if the document we got back from the server is the desired file or an error page. | Note that this code checks the HTTP status code (like 200, 404) to see if the document we got back from the server is the desired file or an error page. | ||
− | ===Simple version=== | + | ==== Simple version ==== |
− | <syntaxhighlight> | + | |
+ | <syntaxhighlight lang="pascal"> | ||
... | ... | ||
uses httpsend, | uses httpsend, | ||
Line 155: | Line 165: | ||
end;</syntaxhighlight> | end;</syntaxhighlight> | ||
− | ===Advanced version=== | + | ==== Advanced version ==== |
− | <syntaxhighlight> | + | |
+ | <syntaxhighlight lang="pascal"> | ||
... | ... | ||
uses httpsend | uses httpsend | ||
Line 181: | Line 192: | ||
begin | begin | ||
Sleep(500 * RetryAttempt); | Sleep(500 * RetryAttempt); | ||
+ | HTTPSender.Clear; | ||
HTTPGetResult := HTTPSender.HTTPMethod('GET', URL); | HTTPGetResult := HTTPSender.HTTPMethod('GET', URL); | ||
RetryAttempt := RetryAttempt + 1; | RetryAttempt := RetryAttempt + 1; | ||
Line 207: | Line 219: | ||
</syntaxhighlight> | </syntaxhighlight> | ||
− | === From an HTTP server by parsing URLs: Sourceforge === | + | ==== Simple version with progress ==== |
+ | |||
+ | The following example shows how to get progress information from the HTTP download, as well as the file size. | ||
+ | The file size is retrieved from the header information. | ||
+ | |||
+ | <syntaxhighlight lang="pascal"> | ||
+ | unit uhttpdownloader; | ||
+ | |||
+ | // Essential to change this. The default is {$mode objfpc}{$H+} and does not work. | ||
+ | {$mode Delphi} | ||
+ | |||
+ | interface | ||
+ | |||
+ | uses | ||
+ | Classes, SysUtils, httpsend, blcksock, typinfo; | ||
+ | |||
+ | type | ||
+ | IProgress = interface | ||
+ | procedure ProgressNotification(Text: String; CurrentProgress : integer; MaxProgress : integer); | ||
+ | end; | ||
+ | |||
+ | type | ||
+ | { THttpDownloader } | ||
+ | |||
+ | THttpDownloader = class | ||
+ | public | ||
+ | function DownloadHTTP(URL, TargetFile: string; ProgressMonitor : IProgress): Boolean; | ||
+ | private | ||
+ | Bytes : Integer; | ||
+ | MaxBytes : Integer; | ||
+ | HTTPSender: THTTPSend; | ||
+ | ProgressMonitor : IProgress; | ||
+ | procedure Status(Sender: TObject; Reason: THookSocketReason; const Value: String); | ||
+ | function GetSizeFromHeader(Header: String):integer; | ||
+ | end; | ||
+ | |||
+ | implementation | ||
+ | |||
+ | function THttpDownloader.DownloadHTTP(URL, TargetFile: string; ProgressMonitor : IProgress): Boolean; | ||
+ | var | ||
+ | HTTPGetResult: Boolean; | ||
+ | begin | ||
+ | Result := False; | ||
+ | Bytes:= 0; | ||
+ | MaxBytes:= -1; | ||
+ | Self.ProgressMonitor:= ProgressMonitor; | ||
+ | |||
+ | HTTPSender := THTTPSend.Create; | ||
+ | try | ||
+ | HTTPSender.Sock.OnStatus:= Status; | ||
+ | HTTPGetResult := HTTPSender.HTTPMethod('GET', URL); | ||
+ | if (HTTPSender.ResultCode >= 100) and (HTTPSender.ResultCode<=299) then begin | ||
+ | HTTPSender.Document.SaveToFile(TargetFile); | ||
+ | Result := True; | ||
+ | end; | ||
+ | finally | ||
+ | HTTPSender.Free; | ||
+ | end; | ||
+ | end; | ||
+ | |||
+ | procedure THttpDownloader.Status(Sender: TObject; Reason: THookSocketReason; const Value: String); | ||
+ | var | ||
+ | V, currentHeader: String; | ||
+ | i: integer; | ||
+ | begin | ||
+ | //try to get filesize from headers | ||
+ | if (MaxBytes = -1) then | ||
+ | begin | ||
+ | for i:= 0 to HTTPSender.Headers.Count - 1 do | ||
+ | begin | ||
+ | currentHeader:= HTTPSender.Headers[i]; | ||
+ | MaxBytes:= GetSizeFromHeader(currentHeader); | ||
+ | if MaxBytes <> -1 then break; | ||
+ | end; | ||
+ | end; | ||
+ | |||
+ | V := GetEnumName(TypeInfo(THookSocketReason), Integer(Reason)) + ' ' + Value; | ||
+ | |||
+ | if Reason = THookSocketReason.HR_ReadCount then | ||
+ | begin | ||
+ | Bytes:= Bytes + StrToInt(Value); | ||
+ | ProgressMonitor.ProgressNotification(V, Bytes, MaxBytes); | ||
+ | end; | ||
+ | end; | ||
+ | |||
+ | function THttpDownloader.GetSizeFromHeader(Header: String): integer; | ||
+ | var | ||
+ | item : TStringList; | ||
+ | begin | ||
+ | Result:= -1; | ||
+ | |||
+ | if Pos('Content-Length:', Header) <> 0 then | ||
+ | begin | ||
+ | item:= TStringList.Create(); | ||
+ | item.Delimiter:= ':'; | ||
+ | item.StrictDelimiter:=true; | ||
+ | item.DelimitedText:=Header; | ||
+ | if item.Count = 2 then | ||
+ | begin | ||
+ | Result:= StrToInt(Trim(item[1])); | ||
+ | end; | ||
+ | end; | ||
+ | end; | ||
+ | |||
+ | end. | ||
+ | </syntaxhighlight> | ||
+ | |||
+ | What are we doing here? | ||
+ | |||
+ | First of all we look into the headers to get the file size. We have to wait and check if the header is there. The first events do not contain the Content-Length: information. | ||
+ | |||
+ | Once found, we extract that information. There are several events popping up here, which you can react to. But we only check for THookSocketReason.HR_ReadCount in that example. | ||
+ | |||
+ | "HR_ReadCount" provides us with the information how many bytes where read since the last event. | ||
+ | |||
+ | The progress is then reported to the UI: | ||
+ | |||
+ | <syntaxhighlight lang="pascal"> | ||
+ | procedure TMainForm.ProgressNotification(Text: String; CurrentProgress: integer; MaxProgress: integer); | ||
+ | begin | ||
+ | if (MaxProgress <> -1) then | ||
+ | begin | ||
+ | ProgressBar.Max:= MaxProgress; | ||
+ | end; | ||
+ | |||
+ | ProgressBar.Position:= CurrentProgress; | ||
+ | memoStatus.Lines.Add(Text); | ||
+ | Application.ProcessMessages; | ||
+ | end; | ||
+ | </syntaxhighlight> | ||
+ | |||
+ | So, the final main unit will be: | ||
+ | |||
+ | <syntaxhighlight lang="pascal"> | ||
+ | unit uMain; | ||
+ | |||
+ | {$mode Delphi} | ||
+ | |||
+ | interface | ||
+ | |||
+ | uses | ||
+ | Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs, StdCtrls, ComCtrls, httpsend, blcksock, typinfo, | ||
+ | uhttpdownloader; | ||
+ | |||
+ | type | ||
+ | |||
+ | { TMainForm } | ||
+ | |||
+ | TMainForm = class(TForm, IProgress) | ||
+ | btnStartDownload: TButton; | ||
+ | edtUrl: TEdit; | ||
+ | labelUrl: TLabel; | ||
+ | memoStatus: TMemo; | ||
+ | ProgressBar: TProgressBar; | ||
+ | SaveDialog: TSaveDialog; | ||
+ | procedure btnStartDownloadClick(Sender: TObject); | ||
+ | private | ||
+ | { private declarations } | ||
+ | function GetFileNameFromURL(url: String):string; | ||
+ | public | ||
+ | { public declarations } | ||
+ | procedure ProgressNotification(Text: String; CurrentProgress : integer; MaxProgress : integer); | ||
+ | end; | ||
+ | |||
+ | var | ||
+ | MainForm: TMainForm; | ||
+ | |||
+ | implementation | ||
+ | |||
+ | {$R *.lfm} | ||
+ | |||
+ | { TMainForm } | ||
+ | |||
+ | procedure TMainForm.btnStartDownloadClick(Sender: TObject); | ||
+ | var | ||
+ | fileName: String; | ||
+ | downloader: THttpDownloader; | ||
+ | success: boolean; | ||
+ | begin | ||
+ | fileName:= GetFileNameFromURL(edtUrl.Text); | ||
+ | SaveDialog.FileName:=fileName; | ||
+ | if (SaveDialog.Execute) then | ||
+ | begin | ||
+ | memoStatus.Lines.Clear; | ||
+ | ProgressBar.Position:=0; | ||
+ | downloader:= THttpDownloader.Create(); | ||
+ | success:= downloader.DownloadHTTP(edtUrl.Text, SaveDialog.FileName, Self); | ||
+ | |||
+ | ProgressBar.Position:=0; | ||
+ | if Success then | ||
+ | memoStatus.Lines.Add('Download successful') | ||
+ | else | ||
+ | memoStatus.Lines.Add('Error during download'); | ||
+ | |||
+ | end; | ||
+ | end; | ||
+ | |||
+ | function TMainForm.GetFileNameFromURL(url: String): string; | ||
+ | var i, l : integer; | ||
+ | fileName, current : String; | ||
+ | begin | ||
+ | fileName:= ''; | ||
+ | l:= Length(url); | ||
+ | for i:= l downto 0 do begin | ||
+ | current:= url[i]; | ||
+ | if current <> '/' then | ||
+ | begin | ||
+ | fileName:= current + fileName; | ||
+ | end else begin | ||
+ | Result:= fileName; | ||
+ | break; | ||
+ | end; | ||
+ | end; | ||
+ | end; | ||
+ | |||
+ | procedure TMainForm.ProgressNotification(Text: String; CurrentProgress: integer; MaxProgress: integer); | ||
+ | begin | ||
+ | if (MaxProgress <> -1) then ProgressBar.Max:= MaxProgress; | ||
+ | ProgressBar.Position:= CurrentProgress; | ||
+ | memoStatus.Lines.Add(Text); | ||
+ | Application.ProcessMessages; | ||
+ | end; | ||
+ | |||
+ | end. | ||
+ | </syntaxhighlight> | ||
+ | |||
+ | Reference: https://andydunkel.net/2015/09/09/lazarus_synapse_progress/ | ||
+ | |||
+ | ==== From an HTTP server by parsing URLs: Sourceforge ==== | ||
+ | |||
Please see [[Download from SourceForge]] for an example of downloading from sourceforge.net. | Please see [[Download from SourceForge]] for an example of downloading from sourceforge.net. | ||
− | == From an HTTPS server == | + | === From an HTTPS server === |
− | This is similar to downloading from | + | This is similar to downloading from an HTTP server. In addition you need to [[Synapse#SSL.2FTLS_support|activate SSL/TLS support]] and obtain the binary file(s) for the needed library. Then you can use the same DownloadHTTP function for downloading a file from a URL starting with '''https://'''. |
+ | |||
+ | == SSH/Telnet client sample program == | ||
− | |||
Below you will find a unit that allows you to use telnet/SSH client functionality that uses the synapse tlntsend.pas unit. An example program shows how to use this. | Below you will find a unit that allows you to use telnet/SSH client functionality that uses the synapse tlntsend.pas unit. An example program shows how to use this. | ||
A different, simpler way is illustrated by Leonardo Ramé at [http://leonardorame.blogspot.com/2010/01/synapse-based-ssh-client.html]. His example cannot use telnet and only sends one command, though. | A different, simpler way is illustrated by Leonardo Ramé at [http://leonardorame.blogspot.com/2010/01/synapse-based-ssh-client.html]. His example cannot use telnet and only sends one command, though. | ||
− | == Requirements == | + | === Requirements === |
+ | |||
Apart from the Synapse sources (of which you only need a couple), if you want to use SSH functionality, you will need an encryption library that Synapse uses. If you only use Telnet, you don't need this. | Apart from the Synapse sources (of which you only need a couple), if you want to use SSH functionality, you will need an encryption library that Synapse uses. If you only use Telnet, you don't need this. | ||
Line 225: | Line 468: | ||
* LibSSH2 library. Pascal bindings still in development, but you can use a file with your private key (in OpenSSH format) to authenticate. | * LibSSH2 library. Pascal bindings still in development, but you can use a file with your private key (in OpenSSH format) to authenticate. | ||
− | === Cryptlib === | + | ==== Cryptlib ==== |
+ | |||
* On Windows, download a binary version of the cryptlib DLL (CL32.DLL) and put it in your source directory. If you compile to a different directory or distribute your program, you will need to distribute the DLL as well. | * On Windows, download a binary version of the cryptlib DLL (CL32.DLL) and put it in your source directory. If you compile to a different directory or distribute your program, you will need to distribute the DLL as well. | ||
* On Linux and OSX, install cryptlib via your package manager/other means. When distributing your application, mark cryptlib as a requirement in your .deb/.rpm/whatever package. | * On Linux and OSX, install cryptlib via your package manager/other means. When distributing your application, mark cryptlib as a requirement in your .deb/.rpm/whatever package. | ||
Line 233: | Line 477: | ||
The versions of the cryptlib binary and the bindings must match. | The versions of the cryptlib binary and the bindings must match. | ||
− | === LibSSH2 === | + | {{Note|It seems that cryptlib is not suitable to connect to linux machines, though AIX works. Use SSH2 instead.}} |
+ | |||
+ | ==== LibSSH2 ==== | ||
+ | |||
* On Windows, download a binary version of the libssh2 DLL (LIBSSH2.DLL) and put it in your source directory. If you compile to a different directory or distribute your program, you will need to distribute the DLL as well. | * On Windows, download a binary version of the libssh2 DLL (LIBSSH2.DLL) and put it in your source directory. If you compile to a different directory or distribute your program, you will need to distribute the DLL as well. | ||
− | * On Linux and | + | * On Linux and macOS, install libssh2 via your package manager/other means. When distributing your application: |
+ | ** Linux: mark libssh2 as a requirement in your .deb/.rpm/whatever package. | ||
+ | ** macOS: include libssh2 in your [[Application Bundle]]'s Resources directory. | ||
− | You will also need ssl_libssh2.pas (see below) and the bindings: (libssh2.pas, see [http://www.lazarus.freepascal.org/index.php/topic,15935.msg86465.html#msg86465]). | + | You will also need ssl_libssh2.pas (see below) and the bindings: (libssh2.pas, see [http://www.lazarus.freepascal.org/index.php/topic,15935.msg86465.html#msg86465 this forum post]). The libssh2 binary and the bindings must match. |
− | + | === Synapse libssh2 SSL plugin === | |
− | + | {{Note| plugin is not completed.}} | |
− | {{Note| plugin not completed.}} | ||
− | <syntaxhighlight> | + | <syntaxhighlight lang="pascal"> |
{ | { | ||
ssl_libssh2.pas version 0.2 | ssl_libssh2.pas version 0.2 | ||
Line 364: | Line 612: | ||
if not SSHCheck(libssh2_session_startup(FSession, FSocket.Socket)) then | if not SSHCheck(libssh2_session_startup(FSession, FSocket.Socket)) then | ||
exit; | exit; | ||
− | if FSocket.SSL.PrivateKeyFile<>'' then | + | if (FSocket.SSL.PrivateKeyFile<>'') then |
− | if (not SSHCheck(libssh2_userauth_publickey_fromfile(FSession, PChar(FSocket.SSL.Username), nil, PChar(FSocket.SSL.PrivateKeyFile), PChar(FSocket.SSL.KeyPassword)))) and | + | begin |
− | + | if (not SSHCheck(libssh2_userauth_publickey_fromfile(FSession, PChar(FSocket.SSL.Username), nil, PChar(FSocket.SSL.PrivateKeyFile), PChar(FSocket.SSL.KeyPassword)))) then | |
− | + | exit; | |
+ | end | ||
+ | else | ||
+ | if (FSocket.SSL.Username<>'') and (FSocket.SSL.Password<>'') then | ||
+ | begin | ||
+ | if (not SSHCheck(libssh2_userauth_password(FSession, PChar(FSocket.SSL.Username), PChar(FSocket.SSL.Password)))) then | ||
+ | exit; | ||
+ | end; | ||
FChannel := libssh2_channel_open_session(FSession); | FChannel := libssh2_channel_open_session(FSession); | ||
if not assigned(FChannel) then | if not assigned(FChannel) then | ||
begin | begin | ||
− | + | SSHCheck(-1); // get error | |
− | FLastError:=-999; | + | if FLastError = 0 then |
− | + | begin | |
+ | FLastError := -999; // unknown error | ||
+ | FLastErrorDesc := 'Cannot open session'; | ||
+ | end; | ||
exit; | exit; | ||
end; | end; | ||
Line 433: | Line 691: | ||
</syntaxhighlight> | </syntaxhighlight> | ||
− | == Terminal client class == | + | === Terminal client class === |
+ | |||
The telnetsshclient.pas unit below wraps around the Synapse tlntsend.pas unit and abstracts logging in, sending commands and receiving output and logging out. | The telnetsshclient.pas unit below wraps around the Synapse tlntsend.pas unit and abstracts logging in, sending commands and receiving output and logging out. | ||
Line 440: | Line 699: | ||
This unit has been lightly tested on a Linux ssh/telnet server. Additional tests welcome. | This unit has been lightly tested on a Linux ssh/telnet server. Additional tests welcome. | ||
− | <syntaxhighlight> | + | <syntaxhighlight lang="pascal"> |
unit telnetsshclient; | unit telnetsshclient; | ||
Line 771: | Line 1,030: | ||
</syntaxhighlight> | </syntaxhighlight> | ||
− | == Example | + | === Example client code === |
− | To use the class we just made, you can use this example application, sshtest.lpr. Note that it needs to be compiled by Lazarus as it needs the LCL components to work with Synapse: | + | |
− | <syntaxhighlight> | + | To use the TTelnetSSHClient class we just made, you can use this example application, sshtest.lpr. Note that it needs to be compiled by Lazarus as it needs the LCL components to work with Synapse: |
+ | |||
+ | <syntaxhighlight lang="pascal"> | ||
program sshtest; | program sshtest; | ||
Line 852: | Line 1,113: | ||
</syntaxhighlight> | </syntaxhighlight> | ||
− | =OAuth v1/Twitter/Plurk integration= | + | == OAuth v1/Twitter/Plurk integration == |
− | |||
− | + | An OAuth v1 library written in FPC that uses Synapse (and is ready for other network libraries like lNet) is available in [[fpctwit]]. FPCtwit also contains FPC Twitter and Plurk example client programs and a Lazarus Twitter client. | |
− | =See also= | + | == Other Web and Networking Articles == |
+ | |||
+ | * [[Portal:Web Development|Web Development Portal]] | ||
+ | * [[Networking]] | ||
+ | * [[Networking libraries]] - comparison of various networking libraries | ||
+ | * [[Brook Framework]] - The perfect Free Pascal framework for your web applications. It's pure Pascal. You don't need to leave your preferred programming language. | ||
+ | * [[Sockets]] - TCP/IP Sockets components | ||
+ | * [[fcl-net]] - Networking library supplied with FPC | ||
+ | * [[lNet]] - Lightweight Networking Components | ||
+ | * [[XML Tutorial]] - XML is often utilized on network communications | ||
+ | * [[FPC and Apache Modules]] | ||
+ | * [[fcl-web]] - Also known as fpWeb, this is a library to develop web applications which can be deployed as cgi, fastcgi or apache modules. | ||
+ | * [[Secure programming | Secure Programming]] | ||
+ | * [[Internet Tools]] - A wrapper around Synapse/wininet/Android's http components simplifying https and redirections, and a XPath/XQuery/CSS Selector/JSONiq engine to process the downloaded pages | ||
+ | |||
+ | == See also == | ||
* [[Download from SourceForge]] Example that uses Synapse to download from an HTTP server that redirects. | * [[Download from SourceForge]] Example that uses Synapse to download from an HTTP server that redirects. | ||
+ | * [https://sourceforge.net/projects/visualsynapse/ Visual Synapse] component wrappers for many parts of Synapse serial and networking library (TvsComPort, TvsWebClient, TvsSniffer, TvsHTTPServer, TvsFTPServer, TvsAuthentication, TvsVisualDNS, TvsVisualHTTP, TvsVisualDUP, TvsVisualTCP, TvsVisualICMP, TvsSocksProxyInfo, TvsIPHelper, TvsSendMail and TvsSynPing). | ||
+ | * [https://forum.lazarus.freepascal.org/index.php/topic,48677.0.html TCP/IP component based on Synapse + a small demo application] | ||
− | =External links= | + | == External links == |
* [http://www.ararat.cz/synapse/ Official site] | * [http://www.ararat.cz/synapse/ Official site] | ||
* [http://synapse.ararat.cz/doc/help/ Official documentation] | * [http://synapse.ararat.cz/doc/help/ Official documentation] | ||
− | * [ | + | * [https://github.com/geby/synapse/wiki Download and Wiki] |
− | |||
− | |||
− | |||
− | |||
− |
Latest revision as of 03:33, 20 February 2024
│
English (en) │
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Synapse provides an easy to use serial port and synchronous TCP/IP library.
Overview
Synapse offers serial port and TCP/IP connectivity. It differs from other libraries that you only require to add some Synapse Pascal source code files to your code; no need for installing packages etc. The only exception is that you will need an external crypto library if you want to use encryption such as SSL/TLS/SSH.
See the documentation on the official site (link below) for more details.
Installation
Installation can be as simple as simply copying over all files to your application directory and adding the relevant Synapse units to your uses clause.
A more elegant and recommended way is compiling the laz_synapse.lpk package so you can use the same units in all your projects.
Synapse download / Wiki info page: Download and Wiki
Support and bug reporting
The Synapse project has a mailing list where support is given and patches can be submitted.
Bug reports can also be mailed to the mailing list.
See the Synapse support page and some well presented on line help
SSL/TLS support
You can use OpenSSL, CryptLib, StreamSecII or OpenStreamSecII SSL support with Synapse. By default, no SSL support is used.
The support is activated by putting the chosen unit name in the uses section in your project. You also have to put the binary library file in your project path (Windows), or install it into your library search path (Linux, macOS, FreeBSD).
Synapse loads SSL library files in runtime as dynamic libraries.
- For detailed information refer to SSL/TLS Plugin Architecture
- Some crypt libraries can be obtained from: http://synapse.ararat.cz/files/crypt/
Missing library
On Linux you need to make sure the required dynamic library is present/installed on your system. In case of cryptlib if the library is not present on the system, an error message appears during linking:
/usr/bin/ld: cannot find -lcl
A similar message will be displayed when using other dynamic libraries.
Web server example
See the Webserver example.
QOTD server query example
See the Quote of the Day server query example.
Sending email
Refer to the Synapse - Email Examples article.
Downloading files
From an FTP server
Given an URL and a (path and) file name, this will download it from an FTP server. It's mostly a wrapper around the Synapse code meant to make downloading easier when handling arbitrary files. If you know exactly what you're going to download where, just a call to Synapse:
FtpGetFile
will get you very far.
function DownloadFTP(URL, TargetFile: string): boolean;
const
FTPPort=21;
FTPScheme='ftp://'; //URI scheme name for FTP URLs
var
Host: string;
Port: integer;
Source: string;
FoundPos: integer;
begin
// Strip out scheme info:
if LeftStr(URL, length(FTPScheme))=FTPScheme then URL:=Copy(URL, length(FTPScheme)+1, length(URL));
// Crude parsing; could have used URI parsing code in FPC packages...
FoundPos:=pos('/', URL);
Host:=LeftStr(URL, FoundPos-1);
Source:=Copy(URL, FoundPos+1, Length(URL));
//Check for port numbers:
FoundPos:=pos(':', Host);
Port:=FTPPort;
if FoundPos>0 then
begin
Host:=LeftStr(Host, FoundPos-1);
Port:=StrToIntDef(Copy(Host, FoundPos+1, Length(Host)),21);
end;
Result:=FtpGetFile(Host, IntToStr(Port), Source, TargetFile, 'anonymous', 'fpc@example.com');
if result=false then writeln('DownloadFTP: error downloading '+URL+'. Details: host: '+Host+'; port: '+Inttostr(Port)+'; remote path: '+Source+' to '+TargetFile);
end;
Example to get list of files in given path
//Use ftpsend unit
function FtpGetDir(const IP, Port, Path, User, Pass: string; DirList: TStringList): Boolean;
var
i: Integer;
s: string;
begin
Result := False;
with TFTPSend.Create do
try
Username := User;
Password := Pass;
TargetHost := IP;
TargetPort := Port;
if not Login then
Exit;
Result := List(Path, False);
for i := 0 to FtpList.Count -1 do
begin
s := FTPList[i].FileName;
DirList.Add(s);
end;
Logout;
finally
Free;
end;
end;
From an HTTP server
Given an URL and a (path and) file name, this will download it from an HTTP server. Note that this code checks the HTTP status code (like 200, 404) to see if the document we got back from the server is the desired file or an error page.
Simple version
...
uses httpsend,
...
function DownloadHTTP(URL, TargetFile: string): Boolean;
var
HTTPGetResult: Boolean;
HTTPSender: THTTPSend;
begin
Result := False;
HTTPSender := THTTPSend.Create;
try
HTTPGetResult := HTTPSender.HTTPMethod('GET', URL);
if (HTTPSender.ResultCode >= 100) and (HTTPSender.ResultCode<=299) then begin
HTTPSender.Document.SaveToFile(TargetFile);
Result := True;
end;
finally
HTTPSender.Free;
end;
end;
Advanced version
...
uses httpsend
...
function DownloadHTTP(URL, TargetFile: string): Boolean;
// Download file; retry if necessary.
// Could use Synapse HttpGetBinary, but that doesn't deal
// with result codes (i.e. it happily downloads a 404 error document)
const
MaxRetries = 3;
var
HTTPGetResult: Boolean;
HTTPSender: THTTPSend;
RetryAttempt: Integer;
begin
Result := False;
RetryAttempt := 1;
HTTPSender := THTTPSend.Create;
try
try
// Try to get the file
HTTPGetResult := HTTPSender.HTTPMethod('GET', URL);
while (HTTPGetResult = False) and (RetryAttempt < MaxRetries) do
begin
Sleep(500 * RetryAttempt);
HTTPSender.Clear;
HTTPGetResult := HTTPSender.HTTPMethod('GET', URL);
RetryAttempt := RetryAttempt + 1;
end;
// If we have an answer from the server, check if the file
// was sent to us.
case HTTPSender.Resultcode of
100..299:
begin
HTTPSender.Document.SaveToFile(TargetFile);
Result := True;
end; //informational, success
300..399: Result := False; // redirection. Not implemented, but could be.
400..499: Result := False; // client error; 404 not found etc
500..599: Result := False; // internal server error
else Result := False; // unknown code
end;
except
// We don't care for the reason for this error; the download failed.
Result := False;
end;
finally
HTTPSender.Free;
end;
end;
Simple version with progress
The following example shows how to get progress information from the HTTP download, as well as the file size. The file size is retrieved from the header information.
unit uhttpdownloader;
// Essential to change this. The default is {$mode objfpc}{$H+} and does not work.
{$mode Delphi}
interface
uses
Classes, SysUtils, httpsend, blcksock, typinfo;
type
IProgress = interface
procedure ProgressNotification(Text: String; CurrentProgress : integer; MaxProgress : integer);
end;
type
{ THttpDownloader }
THttpDownloader = class
public
function DownloadHTTP(URL, TargetFile: string; ProgressMonitor : IProgress): Boolean;
private
Bytes : Integer;
MaxBytes : Integer;
HTTPSender: THTTPSend;
ProgressMonitor : IProgress;
procedure Status(Sender: TObject; Reason: THookSocketReason; const Value: String);
function GetSizeFromHeader(Header: String):integer;
end;
implementation
function THttpDownloader.DownloadHTTP(URL, TargetFile: string; ProgressMonitor : IProgress): Boolean;
var
HTTPGetResult: Boolean;
begin
Result := False;
Bytes:= 0;
MaxBytes:= -1;
Self.ProgressMonitor:= ProgressMonitor;
HTTPSender := THTTPSend.Create;
try
HTTPSender.Sock.OnStatus:= Status;
HTTPGetResult := HTTPSender.HTTPMethod('GET', URL);
if (HTTPSender.ResultCode >= 100) and (HTTPSender.ResultCode<=299) then begin
HTTPSender.Document.SaveToFile(TargetFile);
Result := True;
end;
finally
HTTPSender.Free;
end;
end;
procedure THttpDownloader.Status(Sender: TObject; Reason: THookSocketReason; const Value: String);
var
V, currentHeader: String;
i: integer;
begin
//try to get filesize from headers
if (MaxBytes = -1) then
begin
for i:= 0 to HTTPSender.Headers.Count - 1 do
begin
currentHeader:= HTTPSender.Headers[i];
MaxBytes:= GetSizeFromHeader(currentHeader);
if MaxBytes <> -1 then break;
end;
end;
V := GetEnumName(TypeInfo(THookSocketReason), Integer(Reason)) + ' ' + Value;
if Reason = THookSocketReason.HR_ReadCount then
begin
Bytes:= Bytes + StrToInt(Value);
ProgressMonitor.ProgressNotification(V, Bytes, MaxBytes);
end;
end;
function THttpDownloader.GetSizeFromHeader(Header: String): integer;
var
item : TStringList;
begin
Result:= -1;
if Pos('Content-Length:', Header) <> 0 then
begin
item:= TStringList.Create();
item.Delimiter:= ':';
item.StrictDelimiter:=true;
item.DelimitedText:=Header;
if item.Count = 2 then
begin
Result:= StrToInt(Trim(item[1]));
end;
end;
end;
end.
What are we doing here?
First of all we look into the headers to get the file size. We have to wait and check if the header is there. The first events do not contain the Content-Length: information.
Once found, we extract that information. There are several events popping up here, which you can react to. But we only check for THookSocketReason.HR_ReadCount in that example.
"HR_ReadCount" provides us with the information how many bytes where read since the last event.
The progress is then reported to the UI:
procedure TMainForm.ProgressNotification(Text: String; CurrentProgress: integer; MaxProgress: integer);
begin
if (MaxProgress <> -1) then
begin
ProgressBar.Max:= MaxProgress;
end;
ProgressBar.Position:= CurrentProgress;
memoStatus.Lines.Add(Text);
Application.ProcessMessages;
end;
So, the final main unit will be:
unit uMain;
{$mode Delphi}
interface
uses
Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs, StdCtrls, ComCtrls, httpsend, blcksock, typinfo,
uhttpdownloader;
type
{ TMainForm }
TMainForm = class(TForm, IProgress)
btnStartDownload: TButton;
edtUrl: TEdit;
labelUrl: TLabel;
memoStatus: TMemo;
ProgressBar: TProgressBar;
SaveDialog: TSaveDialog;
procedure btnStartDownloadClick(Sender: TObject);
private
{ private declarations }
function GetFileNameFromURL(url: String):string;
public
{ public declarations }
procedure ProgressNotification(Text: String; CurrentProgress : integer; MaxProgress : integer);
end;
var
MainForm: TMainForm;
implementation
{$R *.lfm}
{ TMainForm }
procedure TMainForm.btnStartDownloadClick(Sender: TObject);
var
fileName: String;
downloader: THttpDownloader;
success: boolean;
begin
fileName:= GetFileNameFromURL(edtUrl.Text);
SaveDialog.FileName:=fileName;
if (SaveDialog.Execute) then
begin
memoStatus.Lines.Clear;
ProgressBar.Position:=0;
downloader:= THttpDownloader.Create();
success:= downloader.DownloadHTTP(edtUrl.Text, SaveDialog.FileName, Self);
ProgressBar.Position:=0;
if Success then
memoStatus.Lines.Add('Download successful')
else
memoStatus.Lines.Add('Error during download');
end;
end;
function TMainForm.GetFileNameFromURL(url: String): string;
var i, l : integer;
fileName, current : String;
begin
fileName:= '';
l:= Length(url);
for i:= l downto 0 do begin
current:= url[i];
if current <> '/' then
begin
fileName:= current + fileName;
end else begin
Result:= fileName;
break;
end;
end;
end;
procedure TMainForm.ProgressNotification(Text: String; CurrentProgress: integer; MaxProgress: integer);
begin
if (MaxProgress <> -1) then ProgressBar.Max:= MaxProgress;
ProgressBar.Position:= CurrentProgress;
memoStatus.Lines.Add(Text);
Application.ProcessMessages;
end;
end.
Reference: https://andydunkel.net/2015/09/09/lazarus_synapse_progress/
From an HTTP server by parsing URLs: Sourceforge
Please see Download from SourceForge for an example of downloading from sourceforge.net.
From an HTTPS server
This is similar to downloading from an HTTP server. In addition you need to activate SSL/TLS support and obtain the binary file(s) for the needed library. Then you can use the same DownloadHTTP function for downloading a file from a URL starting with https://.
SSH/Telnet client sample program
Below you will find a unit that allows you to use telnet/SSH client functionality that uses the synapse tlntsend.pas unit. An example program shows how to use this. A different, simpler way is illustrated by Leonardo Ramé at [1]. His example cannot use telnet and only sends one command, though.
Requirements
Apart from the Synapse sources (of which you only need a couple), if you want to use SSH functionality, you will need an encryption library that Synapse uses. If you only use Telnet, you don't need this.
There are 2 choices:
- Cryptlib library. Advantage: stable. Apparently able to use private keys but these are in some format that is not widely supported.
- LibSSH2 library. Pascal bindings still in development, but you can use a file with your private key (in OpenSSH format) to authenticate.
Cryptlib
- On Windows, download a binary version of the cryptlib DLL (CL32.DLL) and put it in your source directory. If you compile to a different directory or distribute your program, you will need to distribute the DLL as well.
- On Linux and OSX, install cryptlib via your package manager/other means. When distributing your application, mark cryptlib as a requirement in your .deb/.rpm/whatever package.
You will also need the bindings (cryptlib.pas), present in the source distribution of cryptlib.
The versions of the cryptlib binary and the bindings must match.
![Note icon Light bulb](https://upload.wikimedia.org/wikipedia/commons/d/d8/Nuvola_apps_ktip.png)
LibSSH2
- On Windows, download a binary version of the libssh2 DLL (LIBSSH2.DLL) and put it in your source directory. If you compile to a different directory or distribute your program, you will need to distribute the DLL as well.
- On Linux and macOS, install libssh2 via your package manager/other means. When distributing your application:
- Linux: mark libssh2 as a requirement in your .deb/.rpm/whatever package.
- macOS: include libssh2 in your Application Bundle's Resources directory.
You will also need ssl_libssh2.pas (see below) and the bindings: (libssh2.pas, see this forum post). The libssh2 binary and the bindings must match.
Synapse libssh2 SSL plugin
![Note icon Light bulb](https://upload.wikimedia.org/wikipedia/commons/d/d8/Nuvola_apps_ktip.png)
{
ssl_libssh2.pas version 0.2
SSH2 support (draft) plugin for Synapse Library (http://www.ararat.cz/synapse) by LibSSH2 (http://libssh2.org)
Requires: libssh2 pascal interface - http://www.lazarus.freepascal.org/index.php/topic,15935.msg86465.html#msg86465 and
libssh2.dll with OpenSSL.
(С) Alexey Suhinin http://x-alexey.narod.ru
}
{$IFDEF FPC}
{$MODE DELPHI}
{$ENDIF}
{$H+}
unit ssl_libssh2;
interface
uses
SysUtils,
blcksock, synsock,
libssh2;
type
{:@abstract(class implementing CryptLib SSL/SSH plugin.)
Instance of this class will be created for each @link(TTCPBlockSocket).
You not need to create instance of this class, all is done by Synapse itself!}
TSSLLibSSH2 = class(TCustomSSL)
protected
FSession: PLIBSSH2_SESSION;
FChannel: PLIBSSH2_CHANNEL;
function SSHCheck(Value: integer): Boolean;
function DeInit: Boolean;
public
{:See @inherited}
constructor Create(const Value: TTCPBlockSocket); override;
destructor Destroy; override;
function Connect: boolean; override;
function LibName: String; override;
function Shutdown: boolean; override;
{:See @inherited}
function BiShutdown: boolean; override;
{:See @inherited}
function SendBuffer(Buffer: TMemory; Len: Integer): Integer; override;
{:See @inherited}
function RecvBuffer(Buffer: TMemory; Len: Integer): Integer; override;
{:See @inherited}
function WaitingData: Integer; override;
{:See @inherited}
function GetSSLVersion: string; override;
published
end;
implementation
{==============================================================================}
function TSSLLibSSH2.SSHCheck(Value: integer): Boolean;
var
PLastError: PAnsiChar;
ErrMsgLen: Integer;
begin
Result := true;
FLastError := 0;
FLastErrorDesc := '';
if Value<0 then
begin
FLastError := libssh2_session_last_error(FSession, PLastError, ErrMsglen, 0);
FLastErrorDesc := PLastError;
Result := false;
end;
end;
function TSSLLibSSH2.DeInit: Boolean;
begin
if Assigned(FChannel) then
begin
libssh2_channel_free(FChannel);
FChannel := nil;
end;
if Assigned(FSession) then
begin
libssh2_session_disconnect(FSession,'Goodbye');
libssh2_session_free(FSession);
FSession := nil;
end;
FSSLEnabled := False;
Result := true;
end;
constructor TSSLLibSSH2.Create(const Value: TTCPBlockSocket);
begin
inherited Create(Value);
FSession := nil;
FChannel := nil;
end;
destructor TSSLLibSSH2.Destroy;
begin
DeInit;
inherited Destroy;
end;
function TSSLLibSSH2.Connect: boolean;
begin
Result := False;
if SSLEnabled then DeInit;
if (FSocket.Socket <> INVALID_SOCKET) and (FSocket.SSL.SSLType = LT_SSHv2) then
begin
FSession := libssh2_session_init();
if not Assigned(FSession) then
begin
FLastError := -999;
FLastErrorDesc := 'Cannot initialize SSH session';
exit;
end;
if not SSHCheck(libssh2_session_startup(FSession, FSocket.Socket)) then
exit;
if (FSocket.SSL.PrivateKeyFile<>'') then
begin
if (not SSHCheck(libssh2_userauth_publickey_fromfile(FSession, PChar(FSocket.SSL.Username), nil, PChar(FSocket.SSL.PrivateKeyFile), PChar(FSocket.SSL.KeyPassword)))) then
exit;
end
else
if (FSocket.SSL.Username<>'') and (FSocket.SSL.Password<>'') then
begin
if (not SSHCheck(libssh2_userauth_password(FSession, PChar(FSocket.SSL.Username), PChar(FSocket.SSL.Password)))) then
exit;
end;
FChannel := libssh2_channel_open_session(FSession);
if not assigned(FChannel) then
begin
SSHCheck(-1); // get error
if FLastError = 0 then
begin
FLastError := -999; // unknown error
FLastErrorDesc := 'Cannot open session';
end;
exit;
end;
if not SSHCheck(libssh2_channel_request_pty(FChannel, 'vanilla')) then
exit;
if not SSHCheck(libssh2_channel_shell(FChannel)) then
exit;
FSSLEnabled := True;
Result := True;
end;
end;
function TSSLLibSSH2.LibName: String;
begin
Result := 'ssl_libssh2';
end;
function TSSLLibSSH2.Shutdown: boolean;
begin
Result := DeInit;
end;
function TSSLLibSSH2.BiShutdown: boolean;
begin
Result := DeInit;
end;
function TSSLLibSSH2.SendBuffer(Buffer: TMemory; Len: Integer): Integer;
begin
Result:=libssh2_channel_write(FChannel, PChar(Buffer), Len);
SSHCheck(Result);
end;
function TSSLLibSSH2.RecvBuffer(Buffer: TMemory; Len: Integer): Integer;
begin
result:=libssh2_channel_read(FChannel, PChar(Buffer), Len);
SSHCheck(Result);
end;
function TSSLLibSSH2.WaitingData: Integer;
begin
if libssh2_poll_channel_read(FChannel, Result) <> 1 then Result := 0;
end;
function TSSLLibSSH2.GetSSLVersion: string;
begin
Result:=libssh2_version(0);
end;
initialization
if libssh2_init(0)=0 then
SSLImplementation := TSSLLibSSH2;
finalization
libssh2_exit;
end.
Terminal client class
The telnetsshclient.pas unit below wraps around the Synapse tlntsend.pas unit and abstracts logging in, sending commands and receiving output and logging out.
If you only need a telnet client and can live without SSH support, comment out {$DEFINE HAS_SSH_SUPPORT} below so you don't need to have the libssh2 dll.
This unit has been lightly tested on a Linux ssh/telnet server. Additional tests welcome.
unit telnetsshclient;
{ Wrapper around Synapse libraries and SSL library (libssh2+libssl
is used right now)
Download compiled Windows dll from e.g.
http://alxdm.dyndns-at-work.com:808/files/windll_libssh2.zip
Download FreePascal interface files:
http://www.lazarus.freepascal.org/index.php/topic,15935.msg86465.html#msg86465
This unit allows the user to send Telnet or SSH commands and get the output
Thanks to Leonardo Rame
http://leonardorame.blogspot.com/2010/01/synapse-based-ssh-client.html
and Ludo Brands.
Written by Reinier Olislagers 2011.
Modified for libssh2 by Alexey Suhinin 2012.
License of code:
* MIT
* LGPLv2 or later (with FreePascal static linking exception)
* GPLv2 or later
according to your choice.
Free use allowed but please don't sue or blame me.
Uses other libraries/components; different licenses may apply that also can influence the combined/compiled work.
}
{$mode objfpc}{$H+}
{$DEFINE HAS_SSH_SUPPORT} //comment out if only telnet support required
{$DEFINE LIBSSH2}
interface
uses
Classes, SysUtils,
tlntsend
{$IFDEF HAS_SSH_SUPPORT}
{ssl - or actually ssh - libs required by tlntsend}
{$IFDEF LIBSSH2}
ssl_libssh2
{$ELSE}
ssl_cryptlib
{$ENDIF}
{$ENDIF HAS_SSH_SUPPORT} ;
type
TProtocolType = (Telnet, SSH); //Different means of connecting
TServerType = (Unix, Windows); //line endings, mostly
{ TelnetSSHClient }
{ TTelnetSSHClient }
TTelnetSSHClient = class(TTelnetSend)
protected
FConnected: boolean;
FOutputPosition: integer; //Keeps track of position in output stream
FProtocolType: TProtocolType;
FServerLineEnding: string; //depends on FServerType
FServerType: TServerType;
FWelcomeMessage, FTelnetLoginPrompt, FTelnetPasswordPrompt: string;
procedure SetPrivateKeyFile(Value: string);
function GetPrivateKeyFile: string;
{ Based on protocol and servertype, set expected serverside line ending}
procedure DetermineLineEnding;
{ Sets port if no explicit port set. Uses protocol type: SSH or telnet}
procedure DeterminePort;
function GetSessionLog: string;
procedure ProtocolTypeChange(Value: TProtocolType);
function ReceiveData: string; //Can be used to get welcome message etc.
procedure SendData(Data: string);
procedure ServerTypeChange(Value: TServerType);
public
{All output generated during the entire session up to now}
property AllOutput: string read GetSessionLog;
{True if connected to server}
property Connected: boolean read FConnected;
{Name or IP address of host to connect to}
property HostName: string read FTargetHost write FTargetHost;
{Port on host used for connection. If left as 0, it will be determined by protocol type (22 for SSH, 23 for Telnet}
property Port: String read FTargetPort write FTargetPort;
{Location of private key file.}
property PrivateKeyFile: string read GetPrivateKeyFile write SetPrivateKeyFile;
{Telnet login prompt}
property TelnetLoginPrompt: string read FTelnetLoginPrompt write FTelnetLoginPrompt;
{Telnet password prompt}
property TelnetPasswordPrompt: string read FTelnetPasswordPrompt write FTelnetPasswordPrompt;
{Username used when connecting}
property UserName: string read FUserName write FUserName;
{Password used when connecting. Used as passphrase if PrivateKey is used}
property Password: string read FPassword write FPassword;
{Should we talk Telnet or SSH to the server? Defaults to SSH.}
property ProtocolType: TProtocolType read FProtocolType write ProtocolTypeChange;
{Windows or Unix/Linux server? Has effect on line endings. Defaults to Unix. NOTE: untested}
property Servertype: TServerType read FServerType write ServerTypeChange;
{Initial message displayed on logon}
property WelcomeMessage: string read FWelcomeMessage;
{Connect/logon to server. Requires that all authentication, protocol and hostname/port options are correct
Returns descriptive result. You can then use the Connected property.}
function Connect: string;
{If connected, logoff from server}
procedure Disconnect;
{Send command to server and receive result}
function CommandResult(Command: string): string; //Send command and get results
constructor Create;
destructor Destroy; override;
end;
implementation
{ TelnetSSHClient }
procedure TTelnetSSHClient.SetPrivateKeyFile(value: string);
begin
Sock.SSL.PrivateKeyFile := value;
end;
function TTelnetSSHClient.GetPrivateKeyFile: string;
begin
Result := Sock.SSL.PrivateKeyFile;
end;
procedure TTelnetSSHClient.DetermineLineEnding;
begin
case FProtocolType of
SSH:
begin
if FServerType = Unix then
FServerLineEnding := #10 //Unix
else
FServerLineEnding := #13 + #10; //windows
end;
Telnet:
begin
if FServerType = Unix then
FServerLineEnding := #10 //Unix
else
FServerLineEnding := #13 + #10; //windows
end;
else
raise Exception.Create('Unknown protocol type');
end;
end;
procedure Ttelnetsshclient.DeterminePort;
begin
if FTargetPort = '' then
//Set default port for protocol
begin
case FProtocolType of
Telnet: FTargetPort := '23';
SSH: FTargetPort := '22';
else
raise Exception.Create('Unknown protocol type.');
end;
end;
end;
procedure TTelnetSSHClient.ServerTypeChange(Value: Tservertype);
begin
FServerType := Value;
DetermineLineEnding;
end;
function TTelnetSSHClient.Connect: string;
var
Received: string;
begin
result:='Unknown error while connecting';
FOutputPosition := 1; //First character in output stream
FWelcomeMessage := '';
//Just to make sure:
DetermineLineEnding;
DeterminePort;
if FTargetPort='0' then
begin
result:='Port may not be 0.';
exit; //jump out of function
end;
case FProtocolType of
Telnet:
begin
try
if Login then
begin
FConnected := True;
result:='Connected to telnet server.';
end
else
if Sock.LastError<>0 then raise Exception.Create(Sock.LastErrorDesc);
except
on E: Exception do
begin
FConnected:=false;
result:='Error connecting to telnet server '+FTargetHost+':'+
FTargetPort+' as user ' + FUserName +
'. Technical details: '+E.Message;
end;
end;
end;
SSH:
begin
{$IFNDEF HAS_SSH_SUPPORT}
raise Exception.Create(
'SSH support has not been compiled into the telnetsshclient library.');
{$ENDIF HAS_SSH_SUPPORT}
try
if (PrivateKeyFile <> '') and (FPassword <> '') then
Sock.SSL.KeyPassword:=FPassword;
if SSHLogin then
begin
FConnected := True;
result:='Connected to SSH server.';
end
else
begin
if Sock.LastError<>0 then raise Exception.Create(Sock.LastErrorDesc);
if Sock.SSL.LastError<0 then raise Exception.Create(Sock.SSL.LastErrorDesc);
end;
except
on E: Exception do
begin
FConnected:=false;
result:='Error connecting to SSH server '+FTargetHost+':'+
FTargetPort+' as user ' + FUserName +
'. Technical details: '+E.Message;
end;
end;
end;
else
raise Exception.Create('Unknown protocol type');
end;
if FConnected = True then
begin
FWelcomeMessage := ReceiveData;
if FProtocolType=Telnet then
begin
//Unfortunately, we'll have to extract login ourselves
//Hope it applies to all server types.
if (AnsiPos(AnsiLowerCase(FTelnetLoginPrompt),AnsiLowerCase(FWelcomeMessage))>0) then
begin
SendData(UserName);
end;
Received:=ReceiveData;
if (AnsiPos(AnsiLowerCase(FTelnetPasswordPrompt),AnsiLowerCase(Received))>0) then
begin
SendData(Password);
end;
//Receive additional welcome message/message of the day
FWelcomeMessage:=FWelcomeMessage+LineEnding+ReceiveData;
end;
end;
end;
procedure TTelnetSSHClient.Disconnect;
begin
Logout;
FConnected := False;
end;
function TTelnetSSHClient.ReceiveData: string;
begin
Result := '';
while Sock.CanRead(1000) or (Sock.WaitingData > 0) do
begin
Sock.RecvPacket(1000);
Result := Result + Copy(SessionLog, FOutputPosition,
Length(SessionLog));
FOutputPosition := Length(SessionLog) + 1;
end;
end;
procedure Ttelnetsshclient.SendData(Data: String);
begin
Data := Data + FServerLineEnding; //Could be linux, could be Windows
Send(Data);
end;
function TTelnetSSHClient.GetSessionLog: string;
begin
// Gets complete output up to now
Result := SessionLog;
end;
procedure TTelnetSSHClient.ProtocolTypeChange(Value: Tprotocoltype);
begin
FProtocolType := Value;
//Auto-determine port and line ending, if necessary
DeterminePort;
DetermineLineEnding;
end;
function TTelnetSSHClient.CommandResult(Command: string): string;
begin
Result := '';
if FConnected then
begin
SendData(Command);
Result := ReceiveData; //gets too much
end
else
begin
//raise exception
Result := '';
raise Exception.Create('Can only run command when connected');
end;
end;
constructor TTelnetSSHClient.Create;
begin
inherited;
FConnected := False;
FProtocolType := SSH; //Could be telnet, too
FServerType := Unix; //Probably a safe default.
FTelnetLoginPrompt := 'login:';
FTelnetPasswordPrompt := 'password:';
DetermineLineEnding;
DeterminePort;
end;
destructor TTelnetSSHClient.Destroy;
begin
if FConnected then
Disconnect;
inherited Destroy;
end;
end.
Example client code
To use the TTelnetSSHClient class we just made, you can use this example application, sshtest.lpr. Note that it needs to be compiled by Lazarus as it needs the LCL components to work with Synapse:
program sshtest;
{Test program for telnetsshclient
Written by Reinier Olislagers 2011.
Modified for libssh2 by Alexey Suhinin 2012.
License of code:
* MIT
* LGPLv2 or later (with FreePascal static linking exception)
* GPLv2 or later
according to your choice.
Free use allowed but please don't sue or blame me.
Uses other libraries/components; different licenses may apply that also can influence the combined/compiled work.
Run: sshtest <serverIPorhostname> [PrivateKeyFile]
}
{$mode objfpc}{$H+}
{$APPTYPE CONSOLE}
uses
telnetsshclient;
var
comm: TTelnetSSHClient;
Command: string;
begin
writeln('Starting.');
comm:=TTelnetSSHClient.Create;
comm.HostName:= ParamStr(1); //First argument on command line
if comm.HostName='' then
begin
writeln('Please specify hostname on command line.');
halt(1);
end;
comm.PrivateKeyFile := ParamStr(2);
comm.TargetPort:='0'; //auto determine based on protocoltype
comm.UserName:='root'; //change to your situation
comm.Password:='password'; //change to your situation
comm.ProtocolType:=SSH; //Telnet or SSH
writeln(comm.Connect); //Show result of connection
if comm.Connected then
begin
writeln('Server: ' + comm.HostName + ':'+comm.TargetPort+', user: '+comm.UserName);
writeln('Welcome message:');
writeln(comm.WelcomeMessage);
Command:='ls -al';
writeln('*** Sending ' + Command);
writeln('*** Begin result****');
writeln(comm.CommandResult(Command));
writeln('*** End result****');
writeln('');
writeln('');
Command:='df -h';
writeln('*** Sending ' + Command);
writeln('*** Begin result****');
writeln(comm.CommandResult(Command));
writeln('*** End result****');
writeln('');
writeln('');
writeln('All output:');
writeln('*** Begin result****');
writeln(comm.AllOutput);
writeln('*** End result****');
comm.Disconnect;
end
else
begin
writeln('Connection to ' +
comm.HostName + ':' +
comm.TargetPort + ' failed.');
end;
comm.Free;
end.
OAuth v1/Twitter/Plurk integration
An OAuth v1 library written in FPC that uses Synapse (and is ready for other network libraries like lNet) is available in fpctwit. FPCtwit also contains FPC Twitter and Plurk example client programs and a Lazarus Twitter client.
Other Web and Networking Articles
- Web Development Portal
- Networking
- Networking libraries - comparison of various networking libraries
- Brook Framework - The perfect Free Pascal framework for your web applications. It's pure Pascal. You don't need to leave your preferred programming language.
- Sockets - TCP/IP Sockets components
- fcl-net - Networking library supplied with FPC
- lNet - Lightweight Networking Components
- XML Tutorial - XML is often utilized on network communications
- FPC and Apache Modules
- fcl-web - Also known as fpWeb, this is a library to develop web applications which can be deployed as cgi, fastcgi or apache modules.
- Secure Programming
- Internet Tools - A wrapper around Synapse/wininet/Android's http components simplifying https and redirections, and a XPath/XQuery/CSS Selector/JSONiq engine to process the downloaded pages
See also
- Download from SourceForge Example that uses Synapse to download from an HTTP server that redirects.
- Visual Synapse component wrappers for many parts of Synapse serial and networking library (TvsComPort, TvsWebClient, TvsSniffer, TvsHTTPServer, TvsFTPServer, TvsAuthentication, TvsVisualDNS, TvsVisualHTTP, TvsVisualDUP, TvsVisualTCP, TvsVisualICMP, TvsSocksProxyInfo, TvsIPHelper, TvsSendMail and TvsSynPing).
- TCP/IP component based on Synapse + a small demo application