Parse
一種 BaaS 。
RxParse
「找出我留言過的貼文」：
原本的 FindCallback 寫法：
ParseComment.getQuery().whereEqualTo("from", ParseUser.getCurrentUser()).findInBackground(new FindCallback<ParseComment> {
@Override
public done(List<ParseComment> comments, ParseException e) {
if (e != null) return;
ParsePost.getQuery().whereContainedIn("comments", comments).findInBackground(new FindCallback<ParsePost>() {
@Override
public done(List<ParsePost> posts, ParseException e2) {
if (e2 != null) return;
// ...
}
});
}
});
FindCallback 拆解寫法：
getMyCommentedPosts(new FindCallback<ParsePost>() {
@Override
public done(List<ParsePost> posts, ParseException e) {
if (e != null) return;
// ...
}
});
public static void getMyCommentedPosts(FindCallback<ParsePost> findCallback) {
getMyComments(new FindCallback<ParseComment> {
@Override
public done(List<ParseComment> comments, ParseException e) {
if (e != null) {
findCallback.done(null, e);
return;
}
ParsePost.getQuery().whereContainedIn("comments", comments).findInBackground(findCallback);
}
});
}
public static void getMyComments(FindCallback<ParseComment> findCallback) {
ParseComment.getQuery().whereEqualTo("from", ParseUser.getCurrentUser()).findInBackground(findCallback);
}
改成 Bolts Promise 寫法：
ParseComment.getQuery().whereEqualTo("from", ParseUser.getCurrentUser()).findInBackground()
.continueWithTask(new Continuation<List<ParseComment>, Task<List<ParsePost>>>() {
public Task<List<ParsePost>> then(Task<List<ParseComment>> task) throws Exception {
if (task.isFaulted()) return null;
return ParsePost.getQuery().whereContainedIn("comments", task.getResult()).findInBackground();
}
}).onSuccess(new Continuation<List<ParsePost>>, Void>() {
public Void then(Task<List<ParsePost>> task) throws Exception {
List<ParsePost> posts = task.getResult();
// ...
return null;
}
});
Bolts Promise 拆解寫法：
getMyCommentedPostsTask().onSuccess(new Continuation<List<ParsePost>>, Void>() {
public Void then(Task<List<ParsePost>> task) throws Exception {
List<ParsePost> posts = task.getResult();
// ...
return null;
}
});
public static Task<List<ParsePost>> getMyCommentedPostsTask() {
return getMyCommentsTask().continueWithTask(new Continuation<List<ParseComment>, Task<List<ParsePost>>>() {
public Task<List<ParsePost>> then(Task<List<ParseComment>> task) throws Exception {
if (task.isFaulted()) return null;
return ParsePost.getQuery().whereContainedIn("comments", task.getResult()).findInBackground();
}
});
}
public static Task<List<ParseComment>> getMyCommentsTask() {
return ParseComment.getQuery().whereEqualTo("from", ParseUser.getCurrentUser()).findInBackground();
}
RxParse 寫法：
ParseObservable.find(ParseComment.getQuery().whereEqualTo("from", ParseUser.getCurrentUser()))
.toList()
.flatMap(comments -> ParseObservable.find(ParsePost.getQuery().whereContainedIn("comments", comments)))
.subscribe(posts -> {});
RxParse 拆解寫法：
getMyCommentedPosts().subscribe(posts -> {});
public static Observable<ParsePost> getMyCommentedPosts() {
return getMyComments().toList().flatMap(comments -> ParseObservable.find(ParsePost.getQuery().whereContainedIn("comments", comments)));
}
public static Observable<ParseComment> getMyComments() {
return ParseObservable.find(ParseComment.getQuery().whereEqualTo("from", ParseUser.getCurrentUser()));
}
RxParse 測項
@Test
public void testParseObservableAllNextAfterCompleted() {
ParseUser user = mock(ParseUser.class);
ParseUser user2 = mock(ParseUser.class);
ParseUser user3 = mock(ParseUser.class);
List<ParseUser> users = new ArrayList<>();
when(user.getObjectId()).thenReturn("" + user.hashCode());
users.add(user);
when(user2.getObjectId()).thenReturn("" + user2.hashCode());
users.add(user2);
when(user3.getObjectId()).thenReturn("" + user3.hashCode());
users.add(user3);
ParseQueryController queryController = mock(ParseQueryController.class);
ParseCorePlugins.getInstance().registerQueryController(queryController);
Task<List<ParseUser>> task = Task.forResult(users);
when(queryController.findAsync(
any(ParseQuery.State.class),
any(ParseUser.class),
any(Task.class))
).thenReturn(task);
when(queryController.countAsync(
any(ParseQuery.State.class),
any(ParseUser.class),
any(Task.class))).thenReturn(Task.<Integer>forResult(users.size()));
ParseQuery<ParseUser> query = ParseQuery.getQuery(ParseUser.class);
query.setUser(new ParseUser());
final AtomicBoolean completed = new AtomicBoolean(false);
rx.parse.ParseObservable.all(query)
//.observeOn(Schedulers.newThread())
//.subscribeOn(AndroidSchedulers.mainThread())
.subscribe(new Action1<ParseObject>() {
@Override public void call(ParseObject it) {
System.out.println("onNext: " + it.getObjectId());
if (completed.get()) {
fail("Should've onNext after completed.");
}
}
}, new Action1<Throwable>() {
@Override public void call(Throwable e) {
System.out.println("onError: " + e);
}
}, new Action0() {
@Override public void call() {
System.out.println("onCompleted");
completed.set(true);
}
});
try {
ParseTaskUtils.wait(task);
} catch (Exception e) {
// do nothing
}
}
@Test
public void testParseObservableFindNextAfterCompleted() {
ParseUser user = mock(ParseUser.class);
ParseUser user2 = mock(ParseUser.class);
ParseUser user3 = mock(ParseUser.class);
List<ParseUser> users = new ArrayList<>();
users.add(user);
users.add(user2);
users.add(user3);
ParseQueryController queryController = mock(ParseQueryController.class);
ParseCorePlugins.getInstance().registerQueryController(queryController);
Task<List<ParseUser>> task = Task.forResult(users);
when(queryController.findAsync(
any(ParseQuery.State.class),
any(ParseUser.class),
any(Task.class))
).thenReturn(task);
ParseQuery<ParseUser> query = ParseQuery.getQuery(ParseUser.class);
query.setUser(new ParseUser());
final AtomicBoolean completed = new AtomicBoolean(false);
rx.parse.ParseObservable.find(query)
//.observeOn(Schedulers.newThread())
//.subscribeOn(AndroidSchedulers.mainThread())
.subscribe(new Action1<ParseObject>() {
@Override public void call(ParseObject it) {
System.out.println("onNext: " + it);
if (completed.get()) {
fail("Should've onNext after completed.");
}
}
}, new Action1<Throwable>() {
@Override public void call(Throwable e) {
System.out.println("onError: " + e);
}
}, new Action0() {
@Override public void call() {
System.out.println("onCompleted");
completed.set(true);
}
});
try {
ParseTaskUtils.wait(task);
} catch (Exception e) {
// do nothing
}
}
Cloud Coding
Before, cloud code 原本的寫法：
Parse.Cloud.define("signInWithWeibo", function (request, response)) { // 註冊 RPC 名稱
//console.log(request.user + request.params.accessToken); // 取參數，對應 android 手機端 ParseCloud.callFunctionInBackground("signInWithWeibo", Map<K, V>);
// if (where) response.success(obj); // 回傳資料
// else response.error(error); // 回報錯誤
}
After, 1. 改善註冊 RPC 的方法：
defineCloud(signInWithWeibo);
function signInWithWeibo(request, response) {
// ...
}
function defineCloud(func) {
Parse.Cloud.define(func.name, func); // func.name 可以取得 func 的函式名稱
}
After, 2. 將 response 機制隱藏，轉成對應的 Promise ：
function promiseResponse(promise, response) {
promise.then(function (o) {
response.success(o);
}, function (error) {
response.error(error);
})
}
/**
* Returns the session token of available parse user via weibo access token within `request.params.accessToken`.
*
* @param {Object} request Require request.params.accessToken
* @param {Object} response
* @returns {String} sessionToken
*/
function signInWithWeibo(request, response) {
promiseResponse(signInWithWeiboPromise(request.user, request.params.accessToken, request.params.expiresTime), response);
}
/**
* Returns the session token of available parse user via weibo access token.
*
* @param {Parse.User} user
* @param {String} accessToken
* @param {Number} expiresTime
* @returns {Promise<String>} sessionToken
*/
function signInWithWeiboPromise(user, accessToken, expiresTime) {
// ...
}
Parse.Cloud.httpRequest
回傳 {Promise<HTTPResponse>} ，所可以接龍：
/** @returns {Promise<String>} email */
function getEmail(accessToken) {
// GET https://api.weibo.com/2/account/profile/email.json?access_token={access_token}
// 這裡嚴格分離的 params 方式, 好處是未來改成 POST 也統一寫法
return Parse.Cloud.httpRequest({
url: "https://api.weibo.com/2/account/profile/email.json",
params: {
access_token: accessToken
}
}).then(function (httpResponse) {
return JSON.parse(httpResponse.text)[0].email; // [ { email: "[email protected]" } ]
});
}
Promise
Parse.Promise.as("Hello")
Parse.Promise.as("Hello").then(function (hello) {
console.log(hello);
});
Parse.Promise.when(helloPromise, worldPromise)
var helloPromise = Parse.Promise.as("Hello");
var worldPromise = Parse.Promise.as(", world!");
Parse.Promise.when(helloPromise, worldPromise).then(function (hello, world) {
console.log(hello + world);
});
flat and zip:
var helloPromise = Parse.Promise.as("Hello");
var worldPromise = Parse.Promise.as(", world!");
helloPromise.then(function (hello) {
return Parse.Promise.when(Parse.Promise.as(hello), worldPromise);
}).then(function (hello, world) {
console.log(hello + world);
});
Error handling:
/**
* Returns email.
*
* @param {String} accessToken
* @returns {Promise<String>} email
*/
function getEmailAlternative(accessToken) {
return getEmail(accessToken).then(function (email) {
if (!email) return Parse.Promise.error("Invalid email");
return Parse.Promise.as(email);
}, function (error) {
return getUid(accessToken).then(function (uid) {
return Parse.Promise.as(uid + "@weibo.com");
});
});
}
/**
* Returns email
*
* @param {String} accessToken
* @returns {Promise<String>} email
*/
function getEmail(accessToken) {
return Parse.Cloud.httpRequest({
url: "https://api.weibo.com/2/account/profile/email.json",
params: {
access_token: accessToken
}
}).then(function (httpResponse) {
return JSON.parse(httpResponse.text)[0].email; // [ { email: "[email protected]" } ]
});
};
/**
* Returns uid.
*
* @param {String} accessToken
* @returns {Promise<String>} uid
*/
function getUid(accessToken) {
return Parse.Cloud.httpRequest({
url: "https://api.weibo.com/2/account/get_uid.json",
params: {
access_token: accessToken
}
}).then(function (httpResponse) {
return JSON.parse(httpResponse.text).uid; // { uid: 5647447265 }
});
}
ref.