source: lib/oauth2.c @ 4a5d885

/***************************************************************************\
*                                                                           *
*  BitlBee - An IRC to IM gateway                                           *
*  Simple OAuth client (consumer) implementation.                           *
*                                                                           *
*  Copyright 2010-2011 Wilmer van der Gaast <wilmer@gaast.net>              *
*                                                                           *
*  This program is free software; you can redistribute it and/or modify     *
*  it under the terms of the GNU General Public License as published by     *
*  the Free Software Foundation; either version 2 of the License, or        *
*  (at your option) any later version.                                      *
*                                                                           *
*  This program is distributed in the hope that it will be useful,          *
*  but WITHOUT ANY WARRANTY; without even the implied warranty of           *
*  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the            *
*  GNU General Public License for more details.                             *
*                                                                           *
*  You should have received a copy of the GNU General Public License along  *
*  with this program; if not, write to the Free Software Foundation, Inc.,  *
*  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.              *
*                                                                           *
\***************************************************************************/

#include <glib.h>
#include "http_client.h"
#include "oauth2.h"
#include "oauth.h"
#include "url.h"

struct oauth2_service oauth2_service_google =
{
        "https://accounts.google.com/o/oauth2/",
        "783993391592.apps.googleusercontent.com",
        "k5_EV4EQ7jEVCEk3WBwEFfuW",
};

char *oauth2_url( const struct oauth2_service *sp, const char *scope )
{
        return g_strconcat( sp->base_url, "auth"
                            "?scope=", scope,
                            "&response_type=code"
                            "&redirect_uri=urn:ietf:wg:oauth:2.0:oob",
                            "&client_id=", sp->consumer_key,
                            NULL );
}

struct oauth2_access_token_data
{
        oauth2_token_callback func;
        gpointer data;
};

static char *oauth2_json_dumb_get( const char *json, const char *key );
static void oauth2_access_token_done( struct http_request *req );

int oauth2_access_token( const struct oauth2_service *sp,
                         const char *auth_type, const char *auth,
                         oauth2_token_callback func, gpointer data )
{
        GSList *args = NULL;
        char *args_s, *s;
        url_t url_p;
        struct http_request *req;
        struct oauth2_access_token_data *cb_data;
        
        if( !url_set( &url_p, sp->base_url ) )
                return 0;
        
        oauth_params_add( &args, "client_id", sp->consumer_key );
        oauth_params_add( &args, "client_secret", sp->consumer_secret );
        oauth_params_add( &args, "grant_type", auth_type );
        if( strcmp( auth_type, OAUTH2_AUTH_CODE ) == 0 )
        {
                oauth_params_add( &args, "redirect_uri", "urn:ietf:wg:oauth:2.0:oob" );
                oauth_params_add( &args, "code", auth );
        }
        else
        {
                oauth_params_add( &args, "refresh_token", auth );
        }
        args_s = oauth_params_string( args );
        oauth_params_free( &args );
        
        s = g_strdup_printf( "POST %s%s HTTP/1.0\r\n"
                             "Host: %s\r\n"
                             "Content-Type: application/x-www-form-urlencoded\r\n"
                             "Content-Length: %zd\r\n"
                             "Connection: close\r\n"
                             "\r\n"
                             "%s", url_p.file, "token", url_p.host, strlen( args_s ), args_s );
        g_free( args_s );
        
        cb_data = g_new0( struct oauth2_access_token_data, 1 );
        cb_data->func = func;
        cb_data->data = data;
        
        req = http_dorequest( url_p.host, url_p.port, url_p.proto == PROTO_HTTPS,
                              s, oauth2_access_token_done, cb_data );
        
        g_free( s );
        
        if( req == NULL )
                g_free( cb_data );
        
        return req != NULL;
}

static void oauth2_access_token_done( struct http_request *req )
{
        struct oauth2_access_token_data *cb_data = req->data;
        char *atoken = NULL, *rtoken = NULL;
        
        if( req->status_code == 200 )
        {
                atoken = oauth2_json_dumb_get( req->reply_body, "access_token" );
                rtoken = oauth2_json_dumb_get( req->reply_body, "refresh_token" );
        }
        cb_data->func( cb_data->data, atoken, rtoken );
        g_free( atoken );
        g_free( rtoken );
        g_free( cb_data );
}

/* Super dumb. I absolutely refuse to use/add a complete json parser library
   (adding a new dependency to BitlBee for the first time in.. 6 years?) just
   to parse 100 bytes of data. So I have to do my own parsing because OAuth2
   dropped support for XML. (GRRR!) This is very dumb and for example won't
   work for integer values, nor will it strip/handle backslashes. */
static char *oauth2_json_dumb_get( const char *json, const char *key )
{
        int is_key; /* 1 == reading key, 0 == reading value */
        int found_key = 0;
                
        while( json && *json )
        {
                /* Grab strings and see if they're what we're looking for. */
                if( *json == '"' || *json == '\'' )
                {
                        char q = *json;
                        const char *str_start;
                        json ++;
                        str_start = json;
                        
                        while( *json )
                        {
                                /* \' and \" are not string terminators. */
                                if( *json == '\\' && json[1] == q )
                                        json ++;
                                /* But without a \ it is. */
                                else if( *json == q )
                                        break;
                                json ++;
                        }
                        if( *json == '\0' )
                                return NULL;
                        
                        if( is_key && strncmp( str_start, key, strlen( key ) ) == 0 )
                        {
                                found_key = 1;
                        }
                        else if( !is_key && found_key )
                        {
                                char *ret = g_memdup( str_start, json - str_start + 1 );
                                ret[json-str_start] = '\0';
                                return ret;
                        }
                        
                }
                else if( *json == '{' || *json == ',' )
                {
                        found_key = 0;
                        is_key = 1;
                }
                else if( *json == ':' )
                        is_key = 0;
                
                json ++;
        }
        
        return NULL;
}