libPasCURL

It is delphi and object pascal bindings and wrapper around cURL library. libcurl is the library is using for transferring data specified with URL syntax, supporting HTTP, HTTPS, FTP, FTPS, GOPHER, TFTP, SCP, SFTP, SMB, TELNET, DICT, LDAP, LDAPS, FILE, IMAP, SMTP, POP3, RTSP and RTMP.

Table of contents

• Requierements
• Installation
• Usage
• Examples
• Bindings
  • Usage example
• Object wrapper
  • Base functionality
  • Property modules
    • Session modules
    • Response modules
  • HTTP
    • Session modules
    • Response modules
    • Usage example

Requirements

• Embarcadero (R) Rad Studio
• Free Pascal Compiler
• Lazarus IDE (optional)

Library is tested for

• Embarcadero (R) Delphi 10.3 on Windows 7 Service Pack 1 (Version 6.1, Build 7601, 64-bit Edition)
• FreePascal Compiler (3.2.0) and Lazarus IDE (2.0.10) on Ubuntu Linux 5.8.0-33-generic x86_64
• Lazarus 2.2RC2 and the latest curl from brew package manager on MacOS (by Björn Lindh)

Installation

Get the sources and add the source directory to the project search path. For FPC add the source directory to the fpc.cfg file.

Usage

Clone the repository git clone https://github.com/isemenkov/libpascurl.

Add the unit you want to use to the uses clause.

Examples

1. RemoteConnectCStyle simple example for use cURL wrapper in C-Style to connect to remote host.
2. RemoteConnect example how to use curl.http.session.TSession and curl.http.response.TResponse classes to connect to remote host.

Bindings

libpascurl.pas file contains the cURL translated headers to use this library in pascal programs. You can find C API documentation at cURL website.

Usage example

  uses
    libpascurl;

  var
    handle : CURL;
    effectiveUrl, contentType, ip : PChar;
    responseCode, headerSize : Longint;
    contentLength, totalTime : Longword;
    buffer : TStringStream;

  function WriteFunctionCallback (ptr : PChar; size : LongWord;
    nmemb : LongWord; data : Pointer)
  begin
    buffer.WriteString(string(ptr)); 
  end;

  begin
    curl_global_init(CURL_GLOBAL_ALL);
    curl_easy_setopt(handle, CURLOPT_URL, PChar('https://example.dev');
    curl_easy_setopt(handle, CURLOPT_WRITEFUNCTION, @WriteFunctionCallback);
    buffer := TStringStream.Create('');

    if curl_easy_perform = CURLE_OK then
    begin
      New(effectiveUrl);
      New(contentType);
      New(ip);
  
      curl_easy_getinfo(handle, CURLINFO_EFFECTIVE_URL, @effectiveUrl);
      curl_easy_getinfo(handle, CURLINFO_RESPONSE_CODE, @responseCode);
      curl_easy_getinfo(handle, CURLINFO_HEADER_SIZE, @headerSize);
      curl_easy_getinfo(handle, CURLINFO_CONTENT_TYPE, @contentType);
      curl_easy_getinfo(handle, CURLINFO_CONTENT_LENGTH_DOWNLOAD_T, @contentLength);
      curl_easy_getinfo(handle, CURLINFO_LOCAL_IP, @ip);
      curl_easy_getinfo(handle, CURLINFO_TOTAL_TIME_T, @totalTime);

      writeln('URL: ':20,                 effectiveUrl);
      writeln('Response code: ':20,       responseCode);
      writeln('Header size, kB: ':20,     FormatFloat('0.00', headerSize / 1024));
      writeln('Content type: ',           contentType);
      writeln('Content length, kB: ':20,  FormatFloat('0.00', contentLength / 1024));
      writeln('IP: ':20,                  ip);
      writeln('Total time, ms: ':20,      totalTime);
      writeln('==== Content ====');
      writeln(buffer.DataString);
    end;

    curl_global_cleanup; 

  end;

Object wrapper

Base functionality

The library contains a set of classes for creating high-level wrappers around the supported protocols. The source/curl/ folder contains base components that implements specific functionality.

Class	Description
TCURLEasy	It is base class that initialize CURL library and provides error handling functionality.
TSession	It is parent class for sessions of all supported protocols. It provides a TMemoryBuffer for stored downloading/uploading data.
TResponse	It is parent class for server response data.
TPropertyModule	It is base class for all sessions and responses additional functionality modules.

Property modules

Session modules

Module class	Description
TModuleDNS	Class provide properties to setup libCurl DNS options.
TModuleRequest	Class provide properties to setup request properties and callbacks.
TModuleHeader	Class provide properties to setup headers. Can be used only with HTTP-like protocols - HTTP(S), FTP(S), POP3(S), IMAP, SMTP.
TModuleOptions	Class provide properties to setup different libCurl internal options.
TModuleProtocols	Class provide properties to setup libCurl protocol options.
TModuleSocket	Class provide properties to socket setup.
TModuleTCP	Class provide properties to setup TCP protocol options.
TModuleWriter	Class provide properties to setup download callback function.
TModuleReader	Class provide properties to setup upload callback function.
TModuleAuth	Class provide properties to setup auth options.
TModuleTLSAuth	Class provide properties to setup TLS auth authentication options.
TModuleProxy	Class provide properties to setup proxy options.
TModuleSock5	Class provide properties to setup sock5 proxy options.

Response modules

Module class	Description
TModuleContent	Class provide properties to get content data buffer.
TModuleHeader	Class provide properties to response headers. Can be used only with HTTP-like protocols - HTTP(S), FTP(S), POP3(S), IMAP, SMTP.
TModuleRedirect	Class provide information about request redirects.
TModuleSpeed	Class provide speed download/upload information.
TModuleTimeout	Class provide timeouts information.
TModuleInfo	Class provide session information.

HTTP

THTTPSession and THTTPResponse classes implements wrapper about HTTP(S) protocol. This classes extends the functionality of base classes and provided new one that is specific only to this protocol.

This wrapper used or extends the next main modules:

Session modules	Response modules
✔️ TModuleDNS	✔️ TModuleContent
✔️ TModuleHeader	✔️ TModuleHeader
✔️ TModuleOptions	✔️ TModuleRedirect
✔️ TModuleProtocols	✔️ TModuleSpeed
✔️ TModuleSocket	✔️ TModuleTimeout
✔️ TModuleTCP	✔️ TModuleInfo
✔️ TModuleWriter
✔️ TModuleReader
✔️ TModuleRequest
✔️ TModuleAuth
✔️ TModuleTLSAuth
✔️ TModuleProxy
✔️ TModuleSock5

Session modules

Module class	Description
TModuleRedirect	Class provide properties to setup http(s) redirect options.
TModuleHTTP2	Class provide properties to setup HTTP/2 protocol options.
TModuleTimeout	Class provide properties to setup http(s) protocol timeouts options.

Response modules

Module class	Description
TModuleCookie	Class provide cookies data.

Usage example

uses 
  curl.http.session, curl.http.response;
  
var
  Session : THTTP.TSession;
  Response : THHTP.TResponse;

begin
  Session.Url := 'https://github.com/isemenkov';
  Session.Redirect.FollowRedirect := True;
  
  Response := Session.Get;
  
  writeln('Url', Response.Request.Url);
  writeln('Response code', Response.Header.ResponseCode);
  writeln('Content-type', Response.Content.ContentType);
  writeln('Content-size', Response.Content.ContentSize);
  writeln('Content', Response.Content.ToString);
end;