Added an initial cut of the http client code from Steven Van Ingelgem.

--HG--
extra : convert_revision : svn%3Afdd8eb12-d10e-0410-9acb-85c331704f74/trunk%402300

dlib/http_client/http_client.h

+#ifndef DLIB__BROWSER_H
+#define DLIB__BROWSER_H
+
+
+#include <map>
+#include <string>
+#include <vector>
+#include "http_client_abstract.h"
+
+
+// Default timeout after 60 seconds
+#define DEFAULT_TIMEOUT 60000
+
+namespace dlib
+{
+
+    // Function which is called when there is data available.
+    //   Return false to stop the download process...
+    typedef bool (*fnOnDownload)(long already_downloaded, long total_to_download, void * userInfo);
+
+
+    class http_client
+    {
+    public:
+        http_client();
+
+        typedef std::map< std::string, std::string > stringmap;
+        typedef std::map< std::string, stringmap   > string_to_stringmap;
+        typedef std::map< std::string, std::vector<std::string> > string_to_stringvector;
+
+        // Header functions
+        void        set_header(const std::string& header_name, const std::string& header_value);
+        void        set_header(const std::string& header_name, long header_value);
+        std::string get_header(const std::string& header_name) const;
+        void        remove_header(const std::string& header_name);
+        bool        is_header_set(const std::string& header_name) const;
+
+        // This function will clear out all cookies & headers set until now
+        void clear();
+        // This function will clear out the Content-Type header
+        void prepare_for_next_url();
+
+        void set_callback_function( fnOnDownload od, void * _user_info ) { OnDownload = od; user_info = _user_info; }
+
+        void set_cookie(const std::string& cookie_name, const std::string& cookie_value);
+        void set_cookie(const std::string& cookie_name, long cookie_value);
+        void remove_cookie(const std::string& cookie_name);
+
+        void set_user_agent(const std::string& new_agent) { set_header("User-Agent", new_agent); }
+
+
+        void set_timeout( unsigned int milliseconds = DEFAULT_TIMEOUT ) { timeout = milliseconds; }
+
+
+        string_to_stringvector get_returned_headers() const { return returned_headers; }
+        short                  get_http_return     () const { return http_return; }
+        const std::string&     get_body            () const { return returned_body; }
+
+        // POST
+        const std::string& post_url (const std::string& url, const string_to_stringmap& postvars, const string_to_stringmap& filenames = string_to_stringmap());
+        const std::string& post_url (const std::string& url, const std::string& postbuffer);
+        // GET
+        const std::string& get_url  (const std::string& url);
+
+        bool has_error( ) const { return !error_field.empty(); }
+        const std::string& get_error( ) const { return error_field; }
+
+        static std::string urlencode(const std::string& in, bool post_encode = false);
+        static std::string urldecode(const std::string& in);
+    private:
+        bool grab_url(const std::string& url, const std::string& method = "GET", const std::string& post_body = "");
+        std::string build_post(std::string& content_type, const string_to_stringmap& postvars, const string_to_stringmap& filenames) const;
+
+        std::string get_random_string( size_t length = 32 ) const;
+        std::string get_basename( const std::string& filename ) const;
+        std::string strtolower(const std::string& in) const;
+        std::string strtoupper(const std::string& in) const;
+
+        bool parse_url(const std::string& url, std::string& scheme, std::string& user, std::string& pass, std::string& host, short& port, std::string& path) const;
+
+        stringmap headers;
+        stringmap cookies;
+
+        string_to_stringvector returned_headers;
+        short http_return;
+        std::string returned_body, error_field;
+
+        unsigned int timeout;
+
+        fnOnDownload OnDownload;
+        void *       user_info;
+    };
+
+}
+
+#ifdef NO_MAKEFILE
+#include "http_client.cpp"
+#endif
+
+#endif // DLIB__BROWSER_H
+

dlib/http_client/http_client_abstract.h

+#undef DLIB__BROWSER_ABSTRACT_
+#ifdef DLIB__BROWSER_ABSTRACT_
+
+
+
+namespace dlib
+{
+
+    // Function which is called when there is data available.
+    //   Return false to stop the download process...
+    typedef bool (*fnOnDownload)(long already_downloaded, long total_to_download, void * userInfo);
+
+
+// ----------------------------------------------------------------------------------------
+/*
+TODO:
+- Timed cookie support
+- POSTing files: check it!
+- Don't timeout when still downloading!
+*/
+// ----------------------------------------------------------------------------------------
+
+
+    class Browser
+    {
+        /*!
+            WHAT THIS OBJECT REPRESENTS
+                This object represents a possibility for the end user to download webpages (HTTP/1.0)
+                from the internet like a normal webbrowser would do.
+        !*/
+
+    public:
+
+        Browser(
+        );
+        /*!
+            Constructor
+        !*/
+
+        void set_header(
+            const std::string& header_name,
+            const std::string& header_value
+        );
+        /*!
+            Set a header to a certain value
+            Example: set_header("User-Agent", "Internet Explorer")
+        !*/
+
+
+        void set_header(
+            const std::string& header_name,
+            long header_value
+        );
+        /*!
+            Set a header to a certain number
+            Example: set_header("Content-Length", 1234)
+        !*/
+
+        std::string get_header(
+            const std::string& header_name
+        ) const;
+        /*!
+            Get the value of the header or an empty string when it's not set.
+            Example: get_header("Content-Length") would return "1234"
+        !*/
+
+        void remove_header(
+            const std::string& header_name
+        );
+        /*!
+            Removes a certain header
+        !*/
+
+        bool is_header_set(
+            const std::string& header_name
+        ) const;
+        /*!
+            Returns when a header is set and is not empty
+        !*/
+
+        void set_user_agent(
+            const std::string& new_agent
+        ) { set_header("User-Agent", new_agent); }
+        /*!
+            Convenience function for setting a user agent
+        !*/
+
+        void clear(
+        );
+        /*!
+            Clear out all cookies & headers set until now
+        !*/
+
+        void prepare_for_next_url(
+        );
+        /*!
+            Clear out any header and/or cookie which would obstruct getting a next page.
+            At this moment this is cleared:
+                - the Content-Type header
+        !*/
+
+        void set_callback_function( 
+            fnOnDownload od, 
+            void * _user_info 
+        );
+        /*!
+            Set a callback function for one of the following events:
+            - OnDownload: this will tell you how much is downloaded and how much will need to be downloaded
+        !*/
+
+        void set_cookie(
+            const std::string& cookie_name, 
+            const std::string& cookie_value
+        );
+        /*!
+            Set a cookie
+        !*/
+
+        void set_cookie(
+            const std::string& cookie_name, 
+            long cookie_value
+        );
+        /*!
+            Set a cookie
+        !*/
+
+        void remove_cookie(
+            const std::string& cookie_name
+        );
+        /*!
+            Remove a cookie if it's set
+        !*/
+
+        void set_timeout( 
+            unsigned int milliseconds  
+        );
+        /*!
+            Set the maximum time how long a request can take. Setting this to 0 disables
+            this behavior.
+        !*/
+
+        string_to_stringvector get_returned_headers(
+        ) const; 
+        /*!
+            Returns all the headers which are returned in the download of the webpage.
+        !*/
+
+        short get_http_return (
+        ) const;
+        /*!
+            Retrieves the HTTP return code.
+        !*/
+
+        const std::string& get_body (
+        ) const; 
+        /*!
+            Retrieves the HTTP body.
+        !*/
+
+        const std::string& post_url (
+            const std::string& url, 
+            const string_to_stringmap& postvars,
+            const string_to_stringmap& filenames = string_to_stringmap()
+        );
+        /*!
+            POST an url to the internet.
+            You can pass the post variables as well as a list of filenames
+        !*/
+
+        const std::string& post_url (
+            const std::string& url, 
+            const std::string& postbuffer
+        );
+        /*!
+            POST an url to the internet.
+            In this function you have constructed the POST string yourselves
+        !*/
+
+        const std::string& get_url (
+            const std::string& url
+        );
+        /*!
+            GET an url from the internet.
+        !*/
+
+        bool has_error( 
+        ) const;
+        /*!
+            Has there happened an error?
+        !*/
+
+        const std::string& get_error( 
+        ) const;
+        /*!
+            Get the error explanation
+        !*/
+
+        static std::string urlencode(
+            const std::string& in, 
+            bool post_encode = false
+        );
+        /*!
+            Convenience function to URLencode a string
+        !*/
+
+        static std::string urldecode(
+            const std::string& in
+        );
+        /*!
+            Convenience function to URLdecode a string
+        !*/
+
+    };
+
+}
+
+#endif // DLIB__BROWSER_ABSTRACT_
+