Http.java

package com.soundcloud.api;

import org.apache.http.Header;
import org.apache.http.HttpResponse;
import org.apache.http.protocol.HTTP;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.io.IOException;
import java.io.InputStream;

/**
 * Helper class for various HTTP related functions.
 */
public class Http {
    private Http() {
    }

    /**
     * Returns a String representation of the response
     *
     * @param response an HTTP response
     * @return the content body
     * @throws IOException network error
     */
    public static String getString(HttpResponse response) throws IOException {
        InputStream is = response.getEntity().getContent();
        if (is == null) return null;

        int length = ApiWrapper.BUFFER_SIZE;
        Header contentLength = null;
        try {
            contentLength = response.getFirstHeader(HTTP.CONTENT_LEN);
        } catch (UnsupportedOperationException ignored) {
        }

        if (contentLength != null) {
            try {
                length = Integer.parseInt(contentLength.getValue());
            } catch (NumberFormatException ignored) {
            }
        }

        final StringBuilder sb = new StringBuilder(length);
        int n;
        byte[] buffer = new byte[ApiWrapper.BUFFER_SIZE];
        while ((n = is.read(buffer)) != -1) sb.append(new String(buffer, 0, n));
        return sb.toString();
    }

    public static JSONObject getJSON(HttpResponse response) throws IOException {
        final String json = getString(response);
        if (json == null || json.length() == 0) throw new IOException("JSON response is empty");
        try {
            return new JSONObject(json);
        } catch (JSONException e) {
            throw new IOException("could not parse JSON document: "+e.getMessage()+" "+
                    (json.length() > 80 ? (json.substring(0, 79) + "..." ) : json));
        }
    }

    public static String etag(HttpResponse resp) {
        Header etag = resp.getFirstHeader("Etag");
        return etag != null ? etag.getValue() : null;
    }

    public static String formatJSON(String s) {
        try {
            return new JSONObject(s).toString(4);
        } catch (JSONException e) {
            try {
                return new JSONArray(s).toString(4);
            } catch (JSONException e2) {
                return s;
            }
        }
    }
}