OFA Vamp Plugin

/* ------------------------------------------------------------------

   libofa -- the Open Fingerprint Architecture library

   Public Domain (PD) 2006 MusicIP Corporation

   No rights reserved.

-------------------------------------------------------------------*/

#include <stdio.h>

#include <stdlib.h>

#include <string>

#include <map>

#include <expat.h>

#include <curl/curl.h>

#include <curl/types.h>

#include <curl/easy.h>

using namespace std;

#include "protocol.h"

const char *url = "http://ofa.musicdns.org/ofa/1/track"; 

const char *userAgent = "libofa_example";

const char *unknown = "unknown";

// Lookup by fingerprint

const char *request_format = 

    "cid=%s&"       // Client ID

    "cvr=%s&"       // Client Version

    "fpt=%s&"       // Fingerprint

    "rmd=%d&"       // m = 1: return metadata; m = 0: only return id 

    "brt=%d&"       // bitrate (kbps)

    "fmt=%s&"       // File extension (e.g. mp3, ogg, flac)

    "dur=%ld&"      // Length of track (milliseconds)

    "art=%s&"       // Artist name. If there is none, send "unknown"

    "ttl=%s&"       // Track title. If there is none, send "unknown"

    "alb=%s&"       // Album name. If there is none, send "unknown"

    "tnm=%d&"       // Track number in album. If there is none, send "0"

    "gnr=%s&"       // Genre. If there is none, send "unknown"

    "yrr=%s&"       // Year. If there is none, send "0"

    "enc=%s&"       // Encoding. e = true: ISO-8859-15; e = false: UTF-8 (default). Optional.

    "\r\n";

// Lookup by PUID (Most fields drop out)

const char *request_format2 =

    "cid=%s&"       // Client ID

    "cvr=%s&"       // Client Version

    "pid=%s&"       // PUID 

    "rmd=%d&"       // m = 1: return metadata; m = 0: only return id 

    "brt=%d&"       // bitrate (kbps)

    "fmt=%s&"       // File extension (e.g. mp3, ogg, flac)

    "dur=%ld&"      // Length of track (milliseconds)

    "art=%s&"       // Artist name. If there is none, send "unknown"

    "ttl=%s&"       // Track title. If there is none, send "unknown"

    "alb=%s&"       // Album name. If there is none, send "unknown"

    "tnm=%d&"       // Track number in album. If there is none, send "0"

    "gnr=%s&"       // Genre. If there is none, send "unknown"

    "yrr=%s&"       // Year. If there is none, send "0"

    "enc=%s&"       // Encoding. e = true: ISO-8859-15; e = false: UTF-8 (default). Optional.

    "\r\n";

// --------------------------------------------------------------------

// HTTP POST support using standard curl calls

// --------------------------------------------------------------------

size_t data_callback(void *ptr, size_t size, size_t num, void *arg)

{

    string *str = (string *)arg;

    (*str) += string((const char *)ptr, size * num);

    return size * num;

}

long http_post(const string &url, const string &userAgent, const string &postData, string &doc)

{

  CURL              *curl;

  long               ret = 0;

  struct curl_slist *headerlist=NULL;

  headerlist = curl_slist_append(headerlist, "Expect:"); 

  curl_global_init(CURL_GLOBAL_ALL);

  curl = curl_easy_init();

  curl_easy_setopt(curl, CURLOPT_URL, url.c_str());

  curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void *)&doc);

  curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, data_callback);

  curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headerlist);

  curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE, postData.length());

  curl_easy_setopt(curl, CURLOPT_POSTFIELDS, postData.c_str());

  curl_easy_setopt(curl, CURLOPT_POST, 1);

  curl_easy_setopt(curl, CURLOPT_USERAGENT, userAgent.c_str());

  curl_easy_perform(curl);

  curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &ret);

  curl_easy_cleanup(curl);

  curl_slist_free_all (headerlist);

  return ret;

}

// --------------------------------------------------------------------

// XML Parsing support 

// --------------------------------------------------------------------

struct ParseInfo

{

    string path;

    string pcdata;

    TrackInformation *info;

};

void begin_element(void *data, const XML_Char *el, const XML_Char **attr)

{

    map<string, string> attrs;

    for(; *attr;) {

        string key = string((char *)*(attr++));

        string value = string((char *)*(attr++));

        attrs[key] = value;

    }

    ((ParseInfo *)data)->path += string("/") + string(el);

    if (((ParseInfo *)data)->path == "/metadata/track/puid-list/puid")

         ((ParseInfo *)data)->info->setPUID(attrs["id"]);

    ((ParseInfo *)data)->pcdata = "";

}

void end_element(void *data, const XML_Char *el)

{

    string::size_type pos;

    if (((ParseInfo *)data)->path == "/metadata/track/title")

         ((ParseInfo *)data)->info->setTrack(((ParseInfo *)data)->pcdata);

    if (((ParseInfo *)data)->path == "/metadata/track/artist/name")

         ((ParseInfo *)data)->info->setArtist(((ParseInfo *)data)->pcdata);

    pos = ((ParseInfo *)data)->path.rfind("/");

    if (pos != string::npos)

       ((ParseInfo *)data)->path = ((ParseInfo *)data)->path.substr(0, pos);

}

void pc_data(void *data, const XML_Char *charData, int len)

{

    char *temp;

    temp = new char[len + 1];

    strncpy(temp, (char *)charData, len);

    temp[len] = 0;

    ((ParseInfo *)data)->pcdata += string(temp);

    delete temp;

}

bool parse_xml(const string &doc, TrackInformation *info, string &err) 

{

    ParseInfo pinfo;

    err = "";

    pinfo.info = info;

    XML_Parser parser = XML_ParserCreate(NULL);

    XML_SetUserData(parser, (void *)&pinfo);

    XML_SetElementHandler(parser, ::begin_element, ::end_element);

    XML_SetCharacterDataHandler(parser, ::pc_data);

    int ret = XML_Parse(parser, doc.c_str(), doc.length(), 1);

    if (ret)

    {

        XML_ParserFree(parser);

        return true;

    }

    err = string(XML_ErrorString(XML_GetErrorCode(parser)));

    char num[10];

    sprintf(num, "%d", (int)XML_GetCurrentLineNumber(parser));

    err += string(" on line ") + string(num);

    XML_ParserFree(parser);

    return false;

}

// --------------------------------------------------------------------

// Retrieve metadata for fingerprint

// --------------------------------------------------------------------

// Returns true on success

bool retrieve_metadata(string client_key, string client_version,

        TrackInformation *info, bool getMetadata) 

{

    if (!info)

        return false;

    // All metadata fields must be provided before this call if the

    // information is available, as part of the Terms of Service.

    // This helps create a better database for all users of the system.

    //

    // If the fields are not available, you can use default values.

    // Here we check for fields which have no default values.

    if (client_key.length() == 0)

        return false;

    if (client_version.length() == 0)

        return false;

    bool lookupByPrint = false;

    if (info->getPUID().length() == 0) {

        // Lookup by fingerprint

        if (info->getPrint().length() == 0)

            return false;

        if (info->getFormat().length() == 0)

            return false;

        if (info->getLengthInMS() == 0)

            return false;

        lookupByPrint = true;

    }

    // Sloppily estimate the size of the resultant URL. Err on the side of making the string too big.

    int bufSize = strlen(lookupByPrint ? request_format : request_format2) +

            client_key.length() + client_version.length() +

            (lookupByPrint ? info->getPrint().length() : info->getPUID().length()) + 

            16 + // getMetadata ? 1 : 0, 

            16 + // info->getBitrate(),

            16 + //info->getFormat().c_str(), 

            16 + //info->getLengthInMS(), 

            ((info->getArtist().c_str() == 0) ? strlen(unknown) : info->getArtist().length()) +

            ((info->getTrack().c_str() == 0) ?  strlen(unknown) : info->getTrack().length()) +

            ((info->getAlbum().c_str() == 0) ?  strlen(unknown) : info->getAlbum().length()) +

            16 + // info->getTrackNum() + 

            ((info->getGenre().c_str() == 0) ?  strlen(unknown) : info->getGenre().length()) +

            ((info->getYear().c_str() == 0) ? 1 : info->getYear().length()) +

            info->getEncoding().length();

    char *buf = new char[bufSize];

    sprintf(buf, lookupByPrint ? request_format : request_format2, 

            client_key.c_str(), 

            client_version.c_str(),

            lookupByPrint ? info->getPrint().c_str() : info->getPUID().c_str(), 

            getMetadata ? 1 : 0, 

            info->getBitrate(),

            info->getFormat().c_str(), 

            info->getLengthInMS(), 

            (info->getArtist().length() == 0) ? unknown : info->getArtist().c_str(),

            (info->getTrack().length() == 0) ? unknown : info->getTrack().c_str(),

            (info->getAlbum().length() == 0) ? unknown : info->getAlbum().c_str(),

            info->getTrackNum(), 

            (info->getGenre().length() == 0) ? unknown : info->getGenre().c_str(),

            (info->getYear().length() == 0) ? "0" : info->getYear().c_str(),

            info->getEncoding().c_str());

    string response;

//    printf("request: '%s'\n", buf);

    long ret = http_post(url, userAgent, buf, response);

    delete [] buf;

    if (ret != 200)

    {

//             printf("Error: %ld\n", ret);

//             printf("response: %s\n\n", response.c_str());

        return false;

    }

//    printf("response: %s\n\n", response.c_str());

    int q = response.find("<?xml");

    if (q != string::npos) {

        response = response.substr(q);

    }

    string err;

    if (!parse_xml(response, info, err)) {

        // Clears title if it wasn't returned

        info->setTrack("");

        // Clears artists if it wasn't returned

        info->setArtist("");

    }

    return true;

}