Android set up Volley to use from cache

Question

I'm trying to create and use a cache for a server JSON response.

For example:

cache JSON objects to internal memory and use that when we don't have an internet connection.

In the following sample code, I can not find any document about how to cache it with Volley and reuse that when server header for update again don't expire.

Like this: set expiration to header and use cache and try to load again after expiration.

I'm trying to set cache mechanism for this method:

private void makeJsonArryReq() {
    JsonArrayRequest req = new JsonArrayRequest(Const.URL_JSON_ARRAY,
            new Response.Listener<JSONArray>() {
                @Override
                public void onResponse(JSONArray response) {
                    msgResponse.setText(response.toString());
                }
            }, new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {
        }
    });
    AppController.getInstance().addToRequestQueue(req,tag_json_arry);
}

Cache method:

public static Cache.Entry parseIgnoreCacheHeaders(NetworkResponse response) {
    long now = System.currentTimeMillis();

    Map<String, String> headers = response.headers;
    long serverDate = 0;
    String serverEtag = null;
    String headerValue;

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

    serverEtag = headers.get("ETag");

    final long cacheHitButRefreshed = 3 * 60 * 1000; // in 3 minutes cache will be hit, but also refreshed on background
    final long cacheExpired = 24 * 60 * 60 * 1000; // in 24 hours this cache entry expires completely
    final long softExpire = now + cacheHitButRefreshed;
    final long ttl = now + cacheExpired;

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

    return entry;
}

BNK · Accepted Answer · 2016-06-10T01:10:08.220

Please note that if the web service supports caching output, you don't have to use CacheRequest below, because Volley will automatically cache.

For your issue, I use some codes inside parseCacheHeaders (and refering to @oleksandr_yefremov's codes). The following code I have tested. Of course, can use for JsonArrayRequest also. Hope this help!

    JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(0, mUrl, new Response.Listener<JSONObject>() {
        @Override
        public void onResponse(JSONObject response) {
            try {
                mTextView.setText(response.toString(5));
            } catch (JSONException e) {
                mTextView.setText(e.toString());
            }
        }
    }, new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {

        }
    }) {
        @Override
        protected Response<JSONObject> parseNetworkResponse(NetworkResponse response) {
            try {                    
                Cache.Entry cacheEntry = HttpHeaderParser.parseCacheHeaders(response);
                if (cacheEntry == null) {
                    cacheEntry = new Cache.Entry();
                }
                final long cacheHitButRefreshed = 3 * 60 * 1000; // in 3 minutes cache will be hit, but also refreshed on background
                final long cacheExpired = 24 * 60 * 60 * 1000; // in 24 hours this cache entry expires completely
                long now = System.currentTimeMillis();
                final long softExpire = now + cacheHitButRefreshed;
                final long ttl = now + cacheExpired;
                cacheEntry.data = response.data;
                cacheEntry.softTtl = softExpire;
                cacheEntry.ttl = ttl;
                String headerValue;
                headerValue = response.headers.get("Date");
                if (headerValue != null) {
                    cacheEntry.serverDate = HttpHeaderParser.parseDateAsEpoch(headerValue);
                }
                headerValue = response.headers.get("Last-Modified");
                if (headerValue != null) {
                    cacheEntry.lastModified = HttpHeaderParser.parseDateAsEpoch(headerValue);
                }
                cacheEntry.responseHeaders = response.headers;
                final String jsonString = new String(response.data,
                        HttpHeaderParser.parseCharset(response.headers));
                return Response.success(new JSONObject(jsonString), cacheEntry);
            } catch (UnsupportedEncodingException e) {
                return Response.error(new ParseError(e));
            } catch (JSONException e) {
                return Response.error(new ParseError(e));
            }
        }

        @Override
        protected void deliverResponse(JSONObject response) {
            super.deliverResponse(response);
        }

        @Override
        public void deliverError(VolleyError error) {
            super.deliverError(error);
        }

        @Override
        protected VolleyError parseNetworkError(VolleyError volleyError) {
            return super.parseNetworkError(volleyError);
        }
    };

    MySingleton.getInstance(this).addToRequestQueue(jsonObjectRequest);

UPDATE:

If you want a base class, refer to the following codes:

public class CacheRequest extends Request<NetworkResponse> {
    private final Response.Listener<NetworkResponse> mListener;
    private final Response.ErrorListener mErrorListener;

    public CacheRequest(int method, String url, Response.Listener<NetworkResponse> listener, Response.ErrorListener errorListener) {
        super(method, url, errorListener);
        this.mListener = listener;
        this.mErrorListener = errorListener;
    }


    @Override
    protected Response<NetworkResponse> parseNetworkResponse(NetworkResponse response) {
        Cache.Entry cacheEntry = HttpHeaderParser.parseCacheHeaders(response);
        if (cacheEntry == null) {
            cacheEntry = new Cache.Entry();
        }
        final long cacheHitButRefreshed = 3 * 60 * 1000; // in 3 minutes cache will be hit, but also refreshed on background
        final long cacheExpired = 24 * 60 * 60 * 1000; // in 24 hours this cache entry expires completely
        long now = System.currentTimeMillis();
        final long softExpire = now + cacheHitButRefreshed;
        final long ttl = now + cacheExpired;
        cacheEntry.data = response.data;
        cacheEntry.softTtl = softExpire;
        cacheEntry.ttl = ttl;
        String headerValue;
        headerValue = response.headers.get("Date");
        if (headerValue != null) {
            cacheEntry.serverDate = HttpHeaderParser.parseDateAsEpoch(headerValue);
        }
        headerValue = response.headers.get("Last-Modified");
        if (headerValue != null) {
            cacheEntry.lastModified = HttpHeaderParser.parseDateAsEpoch(headerValue);
        }
        cacheEntry.responseHeaders = response.headers;
        return Response.success(response, cacheEntry);
    }

    @Override
    protected void deliverResponse(NetworkResponse response) {
        mListener.onResponse(response);
    }

    @Override
    protected VolleyError parseNetworkError(VolleyError volleyError) {
        return super.parseNetworkError(volleyError);
    }

    @Override
    public void deliverError(VolleyError error) {
        mErrorListener.onErrorResponse(error);
    }
}

Then in MainActivity, you can call like this

CacheRequest cacheRequest = new CacheRequest(0, mUrl, new Response.Listener<NetworkResponse>() {
        @Override
        public void onResponse(NetworkResponse response) {
            try {
                final String jsonString = new String(response.data,
                        HttpHeaderParser.parseCharset(response.headers));
                JSONObject jsonObject = new JSONObject(jsonString);
                mTextView.setText(jsonObject.toString(5));
            } catch (UnsupportedEncodingException | JSONException e) {
                e.printStackTrace();
            }
        }
    }, new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {
            mTextView.setText(error.toString());
        }
    });

    MySingleton.getInstance(this).addToRequestQueue(cacheRequest);

UPDATE WITH FULL SOURCE CODE:

MainActivity.java:

package com.example.cachevolley;

import android.content.Context;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.TextView;
import android.widget.Toast;

import com.android.volley.Cache;
import com.android.volley.NetworkResponse;
import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.HttpHeaderParser;
import com.android.volley.toolbox.Volley;

import org.json.JSONException;
import org.json.JSONObject;

import java.io.UnsupportedEncodingException;

public class MainActivity extends AppCompatActivity {

    private final Context mContext = this;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        final TextView textView = (TextView) findViewById(R.id.textView);

        RequestQueue queue = Volley.newRequestQueue(this);
        String url = "http://192.168.0.100/apitest";

        CacheRequest cacheRequest = new CacheRequest(0, url, new Response.Listener<NetworkResponse>() {
            @Override
            public void onResponse(NetworkResponse response) {
                try {
                    final String jsonString = new String(response.data,
                            HttpHeaderParser.parseCharset(response.headers));
                    JSONObject jsonObject = new JSONObject(jsonString);
                    textView.setText(jsonObject.toString(5));
                    Toast.makeText(mContext, "onResponse:\n\n" + jsonObject.toString(), Toast.LENGTH_SHORT).show();
                } catch (UnsupportedEncodingException | JSONException e) {
                    e.printStackTrace();
                }
            }
        }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                Toast.makeText(mContext, "onErrorResponse:\n\n" + error.toString(), Toast.LENGTH_SHORT).show();
            }
        });

        // Add the request to the RequestQueue.
        queue.add(cacheRequest);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

    private class CacheRequest extends Request<NetworkResponse> {
        private final Response.Listener<NetworkResponse> mListener;
        private final Response.ErrorListener mErrorListener;

        public CacheRequest(int method, String url, Response.Listener<NetworkResponse> listener, Response.ErrorListener errorListener) {
            super(method, url, errorListener);
            this.mListener = listener;
            this.mErrorListener = errorListener;
        }


        @Override
        protected Response<NetworkResponse> parseNetworkResponse(NetworkResponse response) {
            Cache.Entry cacheEntry = HttpHeaderParser.parseCacheHeaders(response);
            if (cacheEntry == null) {
                cacheEntry = new Cache.Entry();
            }
            final long cacheHitButRefreshed = 3 * 60 * 1000; // in 3 minutes cache will be hit, but also refreshed on background
            final long cacheExpired = 24 * 60 * 60 * 1000; // in 24 hours this cache entry expires completely
            long now = System.currentTimeMillis();
            final long softExpire = now + cacheHitButRefreshed;
            final long ttl = now + cacheExpired;
            cacheEntry.data = response.data;
            cacheEntry.softTtl = softExpire;
            cacheEntry.ttl = ttl;
            String headerValue;
            headerValue = response.headers.get("Date");
            if (headerValue != null) {
                cacheEntry.serverDate = HttpHeaderParser.parseDateAsEpoch(headerValue);
            }
            headerValue = response.headers.get("Last-Modified");
            if (headerValue != null) {
                cacheEntry.lastModified = HttpHeaderParser.parseDateAsEpoch(headerValue);
            }
            cacheEntry.responseHeaders = response.headers;
            return Response.success(response, cacheEntry);
        }

        @Override
        protected void deliverResponse(NetworkResponse response) {
            mListener.onResponse(response);
        }

        @Override
        protected VolleyError parseNetworkError(VolleyError volleyError) {
            return super.parseNetworkError(volleyError);
        }

        @Override
        public void deliverError(VolleyError error) {
            mErrorListener.onErrorResponse(error);
        }
    }
}

Manifest file:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.cachevolley" >

    <uses-permission android:name="android.permission.INTERNET" />

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

Layout file:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world" />

</RelativeLayout>

Thanks sir. how to use `protected Response` out of your define syntax such as my pastes code as an `Volley` singleton class. i want to use this defin cache method in all of requests from server and all classes — , Aug 15 '15 at 13:01
At this moment, I have no environment to test, but in my opinion, you can create a custom base class that extends Request or Request. Inside this class, override `parseNetworkResponse` like the above. All other requests/classes will use/extends the base class. — BNK, Aug 15 '15 at 13:23
Ah, I just want to test if the cache is still avaiable or not after phone restarted :) — BNK, Aug 17 '15 at 06:55
after each install application, phone must be restart to working cache? — , Aug 17 '15 at 07:46
Excuse me sir. can i get your test project with this ability? Thanks — , Aug 18 '15 at 03:55
Why so? Is my code above not enough for your project to test? — BNK, Aug 18 '15 at 04:04
oh i'm sorry, testing into my project is difficult now. i'm trying to test that in other project, thanks — , Aug 18 '15 at 04:16
I updated my answer with full source code, I think with them, you can easily create new project (just need replace your new web service url) — BNK, Aug 18 '15 at 04:27
hi sir. can you help me on this topic: http://stackoverflow.com/q/33376564/4790312 — , Oct 27 '15 at 19:22
@BNK any info on this http://stackoverflow.com/questions/34984302/why-volley-diskbasedcache-splicing-without-direct-access-to-the-cache-file-name — LOG_TAG, Jan 25 '16 at 05:10
@LOG_TAG I think it's only to make more unique, if you can debug, you will find that localfilename looks like `602197949-1512839413`. Do you agree that it is "more unique" than `602197949` only? :) . In Javadoc, `@return A pseudo-unique filename` — BNK, Jan 25 '16 at 06:17
@BNK hi sir, can you help me on this topic : http://stackoverflow.com/questions/35389113/android-recache-volley-cache-data-when-device-have-internet-connection — , Feb 15 '16 at 09:18
Pls read to see if it can help http://stackoverflow.com/questions/34064066/tell-volley-not-to-use-cached-data-but-to-initiate-a-new-request/34079943#34079943 :) — BNK, Feb 15 '16 at 09:31
@BNK The `lastModified`on this line `cacheEntry.lastModified = HttpHeaderParser.parseDateAsEpoch(headerValue);` appears undefined in my project. Any help will be appreciated. Thanks — BlackPearl, Jun 09 '16 at 22:06
@BlackPearl please place cursor at Cache.Entry, then press Ctrl-B to open its definition, look for lastModified variable inside the file — BNK, Jun 09 '16 at 23:52
@BlackPearl inside `Cache.java` you will find `public static class Entry` look like at http://pastebin.com/sSeNeQBk. Moreover, if your web service supports output caching, `Volley` will automatically caches, you don't have to use `CacheRequest` as in my code — BNK, Jun 10 '16 at 01:01
@BNK Please help with this http://stackoverflow.com/questions/37739350/volley-wont-catch-my-requests — BlackPearl, Jun 10 '16 at 03:16
For all those have `cacheEntry.lastModified = HttpHeaderParser.parseDateAsEpoch(headerValue);` undefined, make sure you use the last version of volley, check if you don't have any old volley `compile files('libs/httpmime-4.3.jar')` anywhere. If yes, remove it and replace it in your gradle with `dependencies { ... compile 'com.android.volley:volley:1.0.0' }` — Cedriga, Jan 12 '17 at 08:38
@BNK Sir I want to toast like "offline mode" in a case when volley get data from cache hit so I want to know is any event for that in volley. — baldraider, May 31 '17 at 09:09
what is the meaning of "web service supports caching output" — aj0822ArpitJoshi, Nov 28 '17 at 11:57

score 2 · Answer 2 · edited Jun 04 '17 at 16:44

2

If the response is taking from server using String Request then just Replace the Line

return Response.success(new JSONObject(jsonString), cacheEntry);

with this

return Response.success(new String(jsonString), cacheEntry);

It works in my case. Try in your own code.

edited Jun 04 '17 at 16:44

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answered Jun 04 '17 at 16:07

Suman Bakhati

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Android set up Volley to use from cache

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