Android Open Source - FeedListViewDemo Http Header Parser






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Back to project page FeedListViewDemo.

License

The source code is released under:

MIT License

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Java Source Code

/*
 * Copyright (C) 2011 The Android Open Source Project
 *//w w w. j  av a2s . c om
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.volley.toolbox;

import com.android.volley.Cache;
import com.android.volley.NetworkResponse;

import org.apache.http.impl.cookie.DateParseException;
import org.apache.http.impl.cookie.DateUtils;
import org.apache.http.protocol.HTTP;

import java.util.Map;

/**
 * Utility methods for parsing HTTP headers.
 */
public class HttpHeaderParser {

    /**
     * Extracts a {@link Cache.Entry} from a {@link NetworkResponse}.
     *
     * @param response The network response to parse headers from
     * @return a cache entry for the given response, or null if the response is not cacheable.
     */
    public static Cache.Entry parseCacheHeaders(NetworkResponse response) {
        long now = System.currentTimeMillis();

        Map<String, String> headers = response.headers;

        long serverDate = 0;
        long serverExpires = 0;
        long softExpire = 0;
        long maxAge = 0;
        boolean hasCacheControl = false;

        String serverEtag = null;
        String headerValue;

        headerValue = headers.get("Date");
        if (headerValue != null) {
            serverDate = parseDateAsEpoch(headerValue);
        }

        headerValue = headers.get("Cache-Control");
        if (headerValue != null) {
            hasCacheControl = true;
            String[] tokens = headerValue.split(",");
            for (int i = 0; i < tokens.length; i++) {
                String token = tokens[i].trim();
                if (token.equals("no-cache") || token.equals("no-store")) {
                    return null;
                } else if (token.startsWith("max-age=")) {
                    try {
                        maxAge = Long.parseLong(token.substring(8));
                    } catch (Exception e) {
                    }
                } else if (token.equals("must-revalidate") || token.equals("proxy-revalidate")) {
                    maxAge = 0;
                }
            }
        }

        headerValue = headers.get("Expires");
        if (headerValue != null) {
            serverExpires = parseDateAsEpoch(headerValue);
        }

        serverEtag = headers.get("ETag");

        // Cache-Control takes precedence over an Expires header, even if both exist and Expires
        // is more restrictive.
        if (hasCacheControl) {
            softExpire = now + maxAge * 1000;
        } else if (serverDate > 0 && serverExpires >= serverDate) {
            // Default semantic for Expire header in HTTP specification is softExpire.
            softExpire = now + (serverExpires - serverDate);
        }

        Cache.Entry entry = new Cache.Entry();
        entry.data = response.data;
        entry.etag = serverEtag;
        entry.softTtl = softExpire;
        entry.ttl = entry.softTtl;
        entry.serverDate = serverDate;
        entry.responseHeaders = headers;

        return entry;
    }

    /**
     * Parse date in RFC1123 format, and return its value as epoch
     */
    public static long parseDateAsEpoch(String dateStr) {
        try {
            // Parse date in RFC1123 format if this header contains one
            return DateUtils.parseDate(dateStr).getTime();
        } catch (DateParseException e) {
            // Date in invalid format, fallback to 0
            return 0;
        }
    }

    /**
     * Returns the charset specified in the Content-Type of this header,
     * or the HTTP default (ISO-8859-1) if none can be found.
     */
    public static String parseCharset(Map<String, String> headers) {
        String contentType = headers.get(HTTP.CONTENT_TYPE);
        if (contentType != null) {
            String[] params = contentType.split(";");
            for (int i = 1; i < params.length; i++) {
                String[] pair = params[i].trim().split("=");
                if (pair.length == 2) {
                    if (pair[0].equals("charset")) {
                        return pair[1];
                    }
                }
            }
        }

        return HTTP.DEFAULT_CONTENT_CHARSET;
    }
}




Java Source Code List

com.android.volley.AuthFailureError.java
com.android.volley.CacheDispatcher.java
com.android.volley.Cache.java
com.android.volley.DefaultRetryPolicy.java
com.android.volley.ExecutorDelivery.java
com.android.volley.NetworkDispatcher.java
com.android.volley.NetworkError.java
com.android.volley.NetworkResponse.java
com.android.volley.Network.java
com.android.volley.NoConnectionError.java
com.android.volley.ParseError.java
com.android.volley.RequestQueue.java
com.android.volley.Request.java
com.android.volley.ResponseDelivery.java
com.android.volley.Response.java
com.android.volley.RetryPolicy.java
com.android.volley.ServerError.java
com.android.volley.TimeoutError.java
com.android.volley.VolleyError.java
com.android.volley.VolleyLog.java
com.android.volley.toolbox.AndroidAuthenticator.java
com.android.volley.toolbox.Authenticator.java
com.android.volley.toolbox.BasicNetwork.java
com.android.volley.toolbox.ByteArrayPool.java
com.android.volley.toolbox.ClearCacheRequest.java
com.android.volley.toolbox.DiskBasedCache.java
com.android.volley.toolbox.HttpClientStack.java
com.android.volley.toolbox.HttpHeaderParser.java
com.android.volley.toolbox.HttpStack.java
com.android.volley.toolbox.HurlStack.java
com.android.volley.toolbox.ImageLoader.java
com.android.volley.toolbox.ImageRequest.java
com.android.volley.toolbox.JsonArrayRequest.java
com.android.volley.toolbox.JsonObjectRequest.java
com.android.volley.toolbox.JsonRequest.java
com.android.volley.toolbox.NetworkImageView.java
com.android.volley.toolbox.NoCache.java
com.android.volley.toolbox.PoolingByteArrayOutputStream.java
com.android.volley.toolbox.RequestFuture.java
com.android.volley.toolbox.StringRequest.java
com.android.volley.toolbox.Volley.java
io.bxbxbai.androiddemos.AppController.java
io.bxbxbai.androiddemos.ApplicationTest.java
io.bxbxbai.androiddemos.MainActivity.java
io.bxbxbai.androiddemos.activity.BaseActivity.java
io.bxbxbai.androiddemos.activity.FeedListActivity.java
io.bxbxbai.androiddemos.adapter.FeedListAdapter.java
io.bxbxbai.androiddemos.adapter.SimpleBaseAdapter.java
io.bxbxbai.androiddemos.data.FeedItem.java
io.bxbxbai.androiddemos.data.FeedResult.java
io.bxbxbai.androiddemos.utils.BitmapUtils.java
io.bxbxbai.androiddemos.utils.GsonRequest.java
io.bxbxbai.androiddemos.utils.ListViewUtils.java
io.bxbxbai.androiddemos.utils.LruBitmapCache.java
io.bxbxbai.androiddemos.utils.RequestManager.java
io.bxbxbai.androiddemos.utils.TaskUtils.java
io.bxbxbai.androiddemos.utils.ToastUtils.java
io.bxbxbai.androiddemos.utils.VersionUtils.java
io.bxbxbai.androiddemos.utils.ViewFinder.java
io.bxbxbai.androiddemos.view.FeedImageView.java