Promise is resolved when network connection is discontinued and file only partially downloaded

[buesing]

RNFB version 0.10.5
RN version 0.45.1

            RNFetchBlob.config({
              fileCache: true,
              path: getSavedPathName(session)
            })
              .fetch('GET', session.url)
              .then(resolve)
              .catch(e => {
                removeSession(session)
                reject(e)
              })

I'm using this piece of code to download video files. If the network goes down during download, the promise still resolves, and I end up with a half-downloaded file that is saved. I tested this by quickly turning off wifi during the download. In my opinion, if possible, the promise should be rejected in this case. If that is not possible, is there an easy way to check if the file download has completed? Is it possible to get the requested file size and then compare them with the file on disk once completed? Any other ideas?

[tingaloo]

I was actually working on this recently,

add this line to end of your .catch block

    RNFetchBlob.fs.unlink(getSavedPathName(session)).then(() => {
      console.log('removed all temporary files');
    })

This will clear all files in that particular folder since you are using fileCache.

See cache file management

EDIT: I think i misunderstood your question and am actually working on something even more similar to your problem. I am running an array of fetches Promise.all([.. , .. ,..)] and they complete AFTER the catch block evokes. I find the write promises complete after the entire chain is complete which is annoying to debug.

[jankarres]

I had the same issue. This seems to happen at any kind of network change. I wrote the following filesize checking. The expectedContentLength is provided by the HTTP header of the request and actualContentLength by the filesize of the written file.

I you do not use async/await, you have to split the awaited promise in a separate then-chain.

const downloadTask = RNFetchBlob
    .config(config)
    .fetch("GET", audioUrl);

downloadTask
    .then(async (res) => {
        if (res && res.respInfo && res.respInfo.headers && res.respInfo.headers["Content-Length"]) {
            const expectedContentLength = res.respInfo.headers["Content-Length"];
            let actualContentLength;

            try {
                const fileStats = await RNFetchBlob.fs.stat(res.path());

                if (!fileStats || !fileStats.size) {
                    throw new Error("FileStatsNotFound");
                }

                actualContentLength = fileStats.size;
            } catch (error) {
                throw new Error("DownloadFailed");
            }

            if (expectedContentLength != actualContentLength) {
                throw new Error("DownloadFailed");
            }
        }

        // Do something else
    })
    .catch((error) => {
        // Catch the "DownloadFailed" error here, if it happens
    });