Angular 2 consume file download

The guards can be used with a simple if-statement, however, TypeScript will narrow the event type inside the statement block for us:. Based on these guards we can now create our custom operator. It'll leverage scan , an operator that allows us to accumulate state for successive values coming through an observable. It takes up to two arguments: First, we provide an accumulator function which will compute the next Download state from the previous one and the current HttpEvent.

Second, we'll pass a seed to scan representing the initial Download state. This seed will represent our download being pending without any progress or content:. Our accumulator will use the previously defined guard to update the Download state over time with information from the HTTP events:.

When we encounter a HttpProgressEvent , we calculate the progress based on the number of bytes already loaded and the total bytes. A download is done when we receive a HttpResponse containing the file contents in its body. When receiving any other events than HttpProgressEvent or HttpResponse , we won't alter the download's state and return it as it is. This way, for example, we can keep the information in the progress property while other events that won't allow us to compute the progress can be ignored for now.

Anything unclear? Let's finally define our custom operator that's using scan with our accumulator and seed :. Notice that this download operator accepts an optional parameter saver.

Once a HTTP response is received, this function is invoked with the download content from inside the accumulator. This allows us to pass in a strategy for persisting the download to a file without directly coupling the operator to FileSaver.

By keeping FileSaver. The download operator can be tested without somehow mocking the saveAs import see here for corresponding tests. If we apply the same pattern to the service, we'll be able to test it just as easy. So let's do that by creating a custom injection token for saveAs in a file called saver. As the docs recommend the service takes care of getting and mapping the data:. Then, on the component we just subscribe and deal with the mapped data.

There are two possibilities. The first , as suggested in the original post, but needs a small correction as noted by Alejandro:. The second way would be to use FileReader. The logic is the same but we can explicitly wait for FileReader to load the data, avoiding the nesting, and solving the async problem. Note: I am trying to download an Excel file, and even though the download is triggered so this answers the question , the file is corrupt. See the answer to this post for avoiding the corrupt file.

ArrayBuffer by default it ResponseContentType. Downloading file through ajax is always a painful process and In my view it is best to let server and browser do this work of content type negotiation. I am using Angular 4 with the 4. I modified an answer I found in Js' Technical Blog which creates a link object, uses it to do the download, then destroys it.

The value of this. I am using this to download attachments, so I know the id, contentType and filename: I am using an MVC api to return the file:. Inside downloadFile data function we need to make block, link, href and file name. I added in the file-saver as Hector Cuevas named in his answer. Using Angular2 v. The journal reducer Though this only sets the correct states used in our application I still wanted to add it in to show the complete pattern. On the component part, you call the service without subscribing to a response.

The solution is referenced from - here. I found the answers so far lacking insight as well as warnings. This is the complete example with the application part and service part after.

Note that we set the observe: "response" to catch the header for the filename. Also note that the Content-Disposition header has to be set and exposed by the server, otherwise the current Angular HttpClient will not pass it on. I added a dotnet core piece of code for that below. I got a solution for downloading from angular 2 without getting corrupt, using spring mvc and angular 2.

Here I am sending byte[] array has return type from the controller. This will give you xls file format. If you want other formats change the mediatype and file name with right extension. I was facing this same case today, I had to download a pdf file as an attachment the file shouldn't be rendered in the browser, but downloaded instead. To achieve that I discovered I had to get the file in an Angular Blob , and, at the same time, add a Content-Disposition header in the response.

Well, I wrote a piece of code inspired by many of the above answers that should easily work in most scenarios where the server sends a file with a content disposition header, without any third-party installations, except rxjs and angular.

As you can see, it's basically pretty much the average backend call from angular, with two changes. Once the file is fetched from the server, I am in principle, delegating the entire task of saving the file to the helper function, which I keep in a separate file, and import into whichever component I need to.

There, no more cryptic GUID filenames! We can use whatever name the server provides, without having to specify it explicitly in the client, or, overwrite the filename provided by the server as in this example.

Also, one can easily, if need be, change the algorithm of extracting the filename from the content-disposition to suit their needs, and everything else will stay unaffected - in case of an error during such extraction, it will just pass 'null' as the filename.

As another answer already pointed out, IE needs some special treatment, as always. But with chromium edge coming in a few months, I wouldn't worry about that while building new apps hopefully. There is also the matter of revoking the URL, but I'm kinda not-so-sure about that, so if someone could help out with that in the comments, that would be awesome. You may also download a file directly from your template where you use download attribute and to [attr.

This simple solution should work on most browsers. This answer suggests that you cannot download files directly with AJAX, primarily for security reasons. So I'll describe what I do in this situation,. Add href attribute in your anchor tag inside the component. Do all following steps in your component.

If a tab opens and closes without downloading anything, i tried following with mock anchor link and it worked. You can return a Blob object from the server and create an anchor tag and set the href property to an object URL created from the Blob. Now clicking on the anchor will download the file. You can set the file name as well.

Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? You can have a look for more details on response type. I have used three ways for downloading file — two ways for Save as functionality and one way to show the file content on browser itself. The above line create a Blob object with file content in response and expecting the file of JSON type.

The above two lines create a URL that will open the file in browser in new window. The above line shows the file content on browser, so it does not give you save as option. The above line uses ready-made FileSaver module that will open the file with Save as option. I have created service class to fetch file data from a server URL but I need to provide a link or button for downloading the file.

In the view file I will give users two options for downloading the same file. I will use link as well as button for downloading the same file from the server. In the service class I have used Http module which may not be found automatically. So I need to register it in providers array of NgModule.

Run the Angular application angular-file-download by executing command ng serve --open. Open, FileAccess. GetFileName fStream. Unknown August 24, at AM.