android - 如何获取流式在线广播的元数据

Question

我正在 Android 2.2 中开发应用程序。我需要获取流式在线广播的元数据，例如 shoutcast。

我使用 IcyStreamMeta 类:

public class IcyStreamMeta<Message> {

protected URL streamUrl;
private Map<String, String> metadata;
private boolean isError;

public IcyStreamMeta(URL streamUrl) {
    setStreamUrl(streamUrl);

    isError = false;
}

/**
 * Get artist using stream's title
 *
 * @return String
 * @throws IOException
 */
public String getArtist() throws IOException {
    Map<String, String> data = getMetadata();

    if (!data.containsKey("StreamTitle"))
        return "";

    String streamTitle = data.get("StreamTitle");
    String title = streamTitle.substring(0, streamTitle.indexOf("-"));
    return title.trim();
}

/**
 * Get title using stream's title
 *
 * @return String
 * @throws IOException
 */
public String getTitle() throws IOException {
    Map<String, String> data = getMetadata();

    if (!data.containsKey("StreamTitle"))
        return "";

    String streamTitle = data.get("StreamTitle");
    String artist = streamTitle.substring(streamTitle.indexOf("-")+1);
    return artist.trim();
}

public Map<String, String> getMetadata() throws IOException {
    if (metadata == null) {
        refreshMeta();
    }

    return metadata;
}

public void refreshMeta() throws IOException {
    retreiveMetadata();
}

private void retreiveMetadata() throws IOException {
    URLConnection con = streamUrl.openConnection();
    con.setRequestProperty("Icy-MetaData", "1");
    con.setRequestProperty("Connection", "close");
    con.setRequestProperty("Accept", null);
    con.connect();

    int metaDataOffset = 0;
    Map<String, List<String>> headers = con.getHeaderFields();
    InputStream stream = con.getInputStream();

    if (headers.containsKey("icy-metaint")) {
        // Headers are sent via HTTP
        metaDataOffset = Integer.parseInt(headers.get("icy-metaint").get(0));
    } else {
        // Headers are sent within a stream
        StringBuilder strHeaders = new StringBuilder();
        char c;
        while ((c = (char)stream.read()) != -1) {
            strHeaders.append(c);
            if (strHeaders.length() > 5 && (strHeaders.substring((strHeaders.length() - 4), strHeaders.length()).equals("\r\n\r\n"))) {
                // end of headers
                break;
            }
        }

        // Match headers to get metadata offset within a stream
        Pattern p = Pattern.compile("\\r\\n(icy-metaint):\\s*(.*)\\r\\n");
        Matcher m = p.matcher(strHeaders.toString());
        if (m.find()) {
            metaDataOffset = Integer.parseInt(m.group(2));
        }
    }

    // In case no data was sent
    if (metaDataOffset == 0) {
        isError = true;
        return;
    }

    // Read metadata
    int b;
    int count = 0;
    int metaDataLength = 4080; // 4080 is the max length
    boolean inData = false;
    StringBuilder metaData = new StringBuilder();
    // Stream position should be either at the beginning or right after headers
    while ((b = stream.read()) != -1) {
        count++;

        // Length of the metadata
        if (count == metaDataOffset + 1) {
            metaDataLength = b * 16;
        }

        if (count > metaDataOffset + 1 && count < (metaDataOffset + metaDataLength)) {              
            inData = true;
        } else {                
            inData = false;             
        }               
        if (inData) {               
            if (b != 0) {                   
                metaData.append((char)b);               
            }           
        }               
        if (count > (metaDataOffset + metaDataLength)) {
            break;
        }

    }

    // Set the data
    metadata = IcyStreamMeta.parseMetadata(metaData.toString());

    // Close
    stream.close();
}

public boolean isError() {
    return isError;
}

public URL getStreamUrl() {
    return streamUrl;
}

public void setStreamUrl(URL streamUrl) {
    this.metadata = null;
    this.streamUrl = streamUrl;
    this.isError = false;
}

public static Map<String, String> parseMetadata(String metaString) {
    Map<String, String> metadata = new HashMap();
    String[] metaParts = metaString.split(";");
    Pattern p = Pattern.compile("^([a-zA-Z]+)=\\'([^\\']*)\\'$");
    Matcher m;
    for (int i = 0; i < metaParts.length; i++) {
        m = p.matcher(metaParts[i]);
        if (m.find()) {
            metadata.put((String)m.group(1), (String)m.group(2));
        }
    }

    return metadata;
}
}

我的主要 Activity 是使用函数:

public void getMeta(){

    timer = new Timer();
    timer.schedule(new TimerTask() {
        public void run() {

            URL url;
            //Message msg = handler.obtainMessage();
            try {
                Log.d("Metadatos","Dentro del try para obtener los metadatos");
                url = new URL("http://relay5.slayradio.org:8000");
                  IcyStreamMeta icy = new IcyStreamMeta(url);
                  //Log.d("Metadatos","El metadata de la url es "+icy.getMetadata().toString());

                    Log.d("Metadatos","El titulo de la cancion es "+icy.getTitle());
                  //msg.obj = icy.getTitle();

                Log.d("Metadatos","El nombre del artista es "+icy.getArtist());
                //handler.sendMessage(msg);
            } catch (MalformedURLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

        }
    }, 0, 10000);

} 

当我运行应用程序时，不获取元数据。我已经看过所有帖子，但找不到解决方案。我需要你的帮助。

问候，胡安。

Answer 1

import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.net.URLConnection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class IcyStreamMeta 
{
    protected URL streamUrl;
    private Map<String, String> metadata;
    private boolean isError;
    private Map<String, String> data;

    public IcyStreamMeta() 
    {
        isError = false;
    }

    /**
     * Get artist using stream's title
     *
     * @return String
     * @throws IOException
     */
    public String getArtist() throws IOException {
        data = getMetadata();

        if (!data.containsKey("StreamTitle"))
            return "";

        String streamTitle = data.get("StreamTitle");
        String title = streamTitle.substring(0, streamTitle.indexOf("-"));
        return title.trim();
    }

    /**
     * Get streamTitle
     *
     * @return String
     * @throws IOException
     */
    public String getStreamTitle() throws IOException 
    {
        data = getMetadata();

        if (!data.containsKey("StreamTitle"))
            return "";

        return data.get("StreamTitle");
    }

    /**
     * Get title using stream's title
     *
     * @return String
     * @throws IOException
     */
    public String getTitle() throws IOException {
        data = getMetadata();

        if (!data.containsKey("StreamTitle"))
            return "";

        String streamTitle = data.get("StreamTitle");
        String artist = streamTitle.substring(streamTitle.indexOf("-")+1);
        return artist.trim();
    }

    public Map<String, String> getMetadata() throws IOException {
        if (metadata == null) {
            refreshMeta();
        }

        return metadata;
    }

    synchronized public void refreshMeta() throws IOException 
    {
        retreiveMetadata();
    }

    synchronized private void retreiveMetadata() throws IOException 
    {
        URLConnection con = streamUrl.openConnection();
        con.setRequestProperty("Icy-MetaData", "1");
        con.setRequestProperty("Connection", "close");
        con.setRequestProperty("Accept", null);
        con.connect();
        int metaDataOffset = 0;
        Map<String, List<String>> headers = con.getHeaderFields();
        InputStream stream = con.getInputStream();

        if (headers.containsKey("icy-metaint")) {
            // Headers are sent via HTTP
            metaDataOffset = Integer.parseInt(headers.get("icy-metaint").get(0));
        } else {
            // Headers are sent within a stream
            StringBuilder strHeaders = new StringBuilder();
            char c;
            while ((c = (char)stream.read()) != -1) 
            {
                strHeaders.append(c);
                if (strHeaders.length() > 5 && (strHeaders.substring((strHeaders.length() - 4), strHeaders.length()).equals("\r\n\r\n"))) {
                    // end of headers
                    break;
                }
            }

            // Match headers to get metadata offset within a stream
            Pattern p = Pattern.compile("\\r\\n(icy-metaint):\\s*(.*)\\r\\n");
            Matcher m = p.matcher(strHeaders.toString());
            if (m.find()) 
            {
                metaDataOffset = Integer.parseInt(m.group(2));
            }
        }

        // In case no data was sent
        if (metaDataOffset == 0) 
        {
            isError = true;
            return;
        }

        // Read metadata
        int b;
        int count = 0;
        int metaDataLength = 4080; // 4080 is the max length
        boolean inData = false;
        StringBuilder metaData = new StringBuilder();
        // Stream position should be either at the beginning or right after headers
        while ((b = stream.read()) != -1) {
            count++;

            // Length of the metadata
            if (count == metaDataOffset + 1) {
                metaDataLength = b * 16;
            }

            if (count > metaDataOffset + 1 && count < (metaDataOffset + metaDataLength)) {              
                inData = true;
            } 
            else 
            {               
                inData = false;             
            }               
            if (inData) 
            {       
                if (b != 0) 
                {           
                    metaData.append((char)b);               
                }
            }
            if (count > (metaDataOffset + metaDataLength)) 
            {
                break;
            }
        }

        // Set the data
        metadata = IcyStreamMeta.parseMetadata(metaData.toString());

        // Close
        stream.close();

    }

    public boolean isError() {
        return isError;
    }

    public URL getStreamUrl() {
        return streamUrl;
    }

    public void setStreamUrl(URL streamUrl) {
        this.metadata = null;
        this.streamUrl = streamUrl;
        this.isError = false;
    }

    public static Map<String, String> parseMetadata(String metaString) 
    {
        Map<String, String> metadata = new HashMap();
        String[] metaParts = metaString.split(";");
        Pattern p = Pattern.compile("^([a-zA-Z]+)=\\'([^\\']*)\\'$");
        Matcher m;
        for (int i = 0; i < metaParts.length; i++) {
            m = p.matcher(metaParts[i]);
            if (m.find()) {
                metadata.put((String)m.group(1), (String)m.group(2));
            }
        }

        return metadata;
    }}

在第二类中创建AsyncTask

protected class MetadataTask2 extends AsyncTask<URL, Void, IcyStreamMeta> 
    {
        @Override
        protected IcyStreamMeta doInBackground(URL... urls) 
        {
            try 
            {
                streamMeta.refreshMeta();
                Log.e("Retrieving MetaData","Refreshed Metadata");
            } 
            catch (IOException e) 
            {
                Log.e(MetadataTask2.class.toString(), e.getMessage());
            }
            return streamMeta;
        }

        @Override
        protected void onPostExecute(IcyStreamMeta result) 
        {
            try 
            {
                title_artist=streamMeta.getStreamTitle();
                Log.e("Retrieved title_artist", title_artist);
                if(title_artist.length()>0)
                {
                    updateMetadata();
                }
                metaFlag=true;
            }
            catch (IOException e) 
            {
                Log.e(MetadataTask2.class.toString(), e.getMessage());
            }
        }
    }

然后如下调用AsyncTask

    streamMeta = new IcyStreamMeta();
    streamMeta.setStreamUrl(new URL(ConstantData.currentStationData.getUrl()));
    metadataTask2=new MetadataTask2();
    metadataTask2.execute(new URL(ConstantData.currentStationData.getUrl()));

在Timer的Run方法中编写代码

    {
    streamMeta.refreshMeta();                               
    String title_artist=streamMeta.getStreamTitle();
    }

上面的代码对我来说效果很好。如果对格式有任何疑问和抱歉，请告诉我。