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我今天遇到了一个有趣的问题。我正在开发一个我们有文件上传的应用程序，我们想要实现一个进度条。该应用程序是使用 React/Redux/Redux-Observable 编写的。我想为上传进度调度操作。这是我为实现它所做的：

withProgress(method, url, body = {}, headers = {}) {
    const progressSubscriber = Subscriber.create();

    return {
        Subscriber: progressSubscriber,
        Request:    this.ajax({ url, method, body, headers, progressSubscriber }),
    };
}

我有一门课用来发出我所有的 ajax 请求。使用传入的参数this.ajax调用。Observable.ajax

export const blobStorageUploadEpic = (action$) => {
    return action$.ofType(a.BLOB_STORAGE_UPLOAD)
    .mergeMap(({ payload }) => {
        const { url, valetKey, blobId, blobData, contentType } = payload;

        const { Subscriber, Request } = RxAjax.withProgress('PUT', `${url}?${valetKey}`, blobData, {
            'x-ms-blob-type': 'BlockBlob',
            'Content-Type':   contentType,
        });

        const requestObservable = Request
        .map(() => ({ type: a.BLOB_STORAGE_UPLOAD_SUCCESS, payload: { blobId } }))
        .catch((err) => Observable.of({ type: a.BLOB_STORAGE_UPLOAD_FAILURE, err }));

        return Observable.fromSubscriber(Subscriber)
        .map((e) => ({ percentage: (e.loaded / e.total) * 100 }))
        .map((percentage) => ({ type: a.BLOB_STORAGE_UPLOAD_PROGRESS, payload: { percentage} }))
        .merge(requestObservable);
    });
};

这是我的史诗。我找回了订阅者，并编写了一个自定义静态方法Observable来接收订阅者。然后我将它与Request（这是一个Observable）合并。

Observable.fromSubscriber = function fromSubscriber(externalSubscriber) {
    return Observable.create((subscriber) => {
        externalSubscriber.next =     (val) => subscriber.next(val);
        externalSubscriber.error =    (err) => subscriber.error(err);
        externalSubscriber.complete = () => subscriber.complete();
    });
};

最后，这是我写的自定义静态方法Observable。我写这篇文章有两个原因。1. 作为其他处理类似问题的人的示例（我花了很多时间试图弄清楚如何在编写自己的之前Observable从 a中创建一个）和 2. 询问这是否是实现此目标的最佳方法Subscriber. rxjs很深，我认为有一种现有的方法可以做到这一点，但我就是找不到。

4

1 回答 1

7

这基本上就是 aSubject的用途，以下内容也应该起作用：

export const blobStorageUploadEpic = (action$) => {
    return action$.ofType(a.BLOB_STORAGE_UPLOAD)
    .mergeMap(({ payload }) => {
        const { url, valetKey, blobId, blobData, contentType } = payload;

        const progressSubscriber = new Rx.Subject();
        const request = Rx.Observable.ajax({
            method: 'PUT',
            url: `${url}?${valetKey}`,
            body: blobData,
            headers: {
                'x-ms-blob-type': 'BlockBlob',
                'Content-Type':   contentType,
            },
            progressSubscriber
        });

        const requestObservable = request
            .map(() => ({ type: a.BLOB_STORAGE_UPLOAD_SUCCESS, payload: { blobId } }))
            .catch((err) => Observable.of({ type: a.BLOB_STORAGE_UPLOAD_FAILURE, err }));

        return progressSubscriber
            .map((e) => ({ percentage: (e.loaded / e.total) * 100 }))
            .map((percentage) => ({ type: a.BLOB_STORAGE_UPLOAD_PROGRESS, payload: { percentage} }))
            .merge(requestObservable);
    });
};

这是一个更通用的示例（live @jsfiddle）：

let data = "";
for (let c = 0; c < 100000; ++c) {
    data += "" + Math.random();
}

const progressSubscriber = new Rx.Subject();
const request = Rx.Observable.ajax({
  method: 'POST',
  url: "/echo/json/",
  body: JSON.stringify({ data }),
  progressSubscriber
});

progressSubscriber
  .merge(request)
  .subscribe(console.log);
于 2017-01-26T23:27:42.107 回答