使用 angular2 - ionic 2 下载文件 [英] Download files with angular2 - ionic 2

问题描述

我有一个 Ionic 2 应用程序，我需要从 soundcloud 下载音频.我已经有了执行请求所需的 url:

I have an Ionic 2 app, and I need to download audios from soundcloud. I already have the url that I need to do the request:

let url = `https://api.soundcloud.com/tracks/${audio.id}/download?client_id=${this.SC_CLIENT_ID}`

我想知道如何做到这一点.我尝试了 FileTransfer:

I want to know how to do this. I tryed with FileTransfer:

public download(audio: any): void {

        this.platform.ready().then(() => {
            console.log("Clickeo para descargar: " + audio.id);

            let url = `https://api.soundcloud.com/tracks/${audio.id}/download?client_id=${this.SC_CLIENT_ID}`;

            let pathToSaveTo: string = '';

            if (this.platform.is('android')) {
                pathToSaveTo = cordova.file.externalApplicationStorageDirectory + audio.id + '.wav';

                let fileTransfer = new Transfer();

                fileTransfer.onProgress(this.onProgress);

                fileTransfer.download(url, pathToSaveTo)
                    .then((entry) => {
                        console.log('download complete: ' + entry.toURL());
                    }, (error) => {

                        let prompt = this.alertCtrl.create({
                            title: 'Error',
                            subTitle: error,
                            buttons: ['Accept']
                        });

                        prompt.present();
                    });
            }
        });

    }

    onProgress = (progressEvent: ProgressEvent) : void => {
        this.ngZone.run(() => {
            if (progressEvent.lengthComputable) {
                let progress: any = Math.round((progressEvent.loaded / progressEvent.total) * 100);
                console.log(progress);
                let toast = this.toastCtrl.create({
                  message: progress,
                  duration: 100
                });
                toast.present();
            }
        });
    }

但它总是下载一个零 KB 的文件.有什么解决办法吗?也许是 angular2 方式，还是我做错了?如果我将此 url 放入浏览器中，并使用正确的音频 id 和 mi 客户端 id，它会开始下载，但不会使用 FileTransfer.

But it always download a zero KB file. Any solution? Maybe angular2 way, or I'm doing it wrong? If I put this url in browser, with the properly audio id and mi client id, it starts to download, but not with FileTransfer.

非常感谢.

伊万.

推荐答案

我的问题是 soundcloud 返回了带有重定向的响应.我必须检测重定向状态并手动重定向到 response.headers.Location

My problem was that soundcloud returned a response with redirect. I had to detect the redirect state and manually redirect to the response.headers.Location

这是工作代码:

public download(localAudio: LocalAudio): void {
    let fileName: string = localAudio.id + '.mp3';

    var audio: StorageAudio = {
        localAudio: localAudio,
        url: `https://api.soundcloud.com/tracks/${localAudio.id}/download?client_id=${this.SC_CLIENT_ID}`,
        fileName: fileName,
        filePath: this.file.dataDirectory + fileName
    };

    if (this.platform.is('ios')) {
        audio.filePath = audio.filePath.replace(/^file:///, '');
    }

    this.toastNotifications.showStartingDownloadMsg();

    this.http.downloadFile(audio.url, {}, {}, audio.filePath).then(response => {
        this.toastNotifications.showDownloadCompleteMsg();

        this.storeAudioInformation(audio);
    }).catch(response => {
        /**
         * Handle redirects if exist.
         */
        if (this.hasRedirection(response)) {
            console.log("Redirect to " + response.headers.Location);
            audio.url = response.headers.Location;

            this.redirectToDownload(audio);
        } else {
            this.toastNotifications.showDownloadErrorMsg();
        }
    });
}

public hasRedirection(response: any): boolean {
    return (response.headers.Location && (response.status === 301 || response.status === 302));
}

public redirectToDownload(audio: StorageAudio): void {
    this.http.downloadFile(audio.url, {}, {}, audio.filePath).then(response => {
        this.toastNotifications.showDownloadCompleteMsg();

        this.storeAudioInformation(audio);
    }).catch(response => {
        console.log("Error catch: " + JSON.stringify(response));
    });
}

这篇关于使用 angular2 - ionic 2 下载文件的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！