AngularJS — Superheroic JavaScript MVW Framework
Jan 23, · Upload, to receive a file a save it in the folder./wwwroot/upload; Download, to recover a file from the folder./wwwroot/upload; Files, to obtain the list of files present in./wwwroot/upload. A possible implementation of the controller may be the following. Jun 06, · Download Excel File In Angular 7; Generate Excel File In Angular 7; read data from JSON in angular 7; TRENDING UP Prototype Design Pattern With Java. Angular 11 CURD Application Using Web API With Material Design. Use Entity Framework Core blogger.com Core With MySQL Database By Code-First Migration On Visual Studio For. CSV files, Excel spreadsheets, Word documents, PDF reports and images are common types of files that a functional Angular web app needs to be able to download to browser. In most cases, files are generated by back-end APIs and sent as blobs in HTTP response body. Downloading files in JavaScript is quite a laborious and boring task.
Angular download file
Downloading files is a common task for web applications. These files could be some PDF, angular download file, ZIP or any other binary or text-based file that you want to make accessible to your angular download file. Here's how you can download files in Angular either with a rather simple link or JavaScript-based for more control and progress indication.
The download operator developed in this article is available in the ngx-operators �� library - a collection of battle-tested RxJS operators for Angular.
You'll use an anchor tag pointing to the file with the href attribute. The download attribute informs the browser that it shouldn't follow the link but rather download the URL target.
You can also specify its value in order to set the name of the file being downloaded, angular download file. You can bind any of these attributes with Angular in order to set the URL and filename dynamically:, angular download file.
Older browsers, like the Internet Explorer, might not recognize the download attribute. If there's no download attribute, the filename for your download will solely depend on the HTTP header Content-Disposition sent by the server that's providing the file, angular download file.
The information from this header might also take precedence even if the download attribute is present. A link-based solution conforms well to HTML standards and lets the browser do most of the work, angular download file. However, if you want more control over the download and would like to display some custom progress indicator you can also download files via Angular's HttpClient.
A file is best represented as a Blob in the browser:. The Blob object represents a blob, which is a file-like object of immutable, raw data -- MDN web docs. By specifying the responseType option we can perform a GET request returning a blob representing the downloaded file.
Let's assume we've got a designated DownloadService doing just that:. A component would then be able to call this service, subscribe to the corresponding observable and eventually save the file like this:. Here, we're creating an anchor tag programmatically when the blob arrives. With URL. Finally, angular download file, we click the link like the user would've done with a regular browser angular download file link.
After the file is downloaded, we'll discard the blob by revoking the object URL we created. This approach is pretty verbose though angular download file might not work smoothly for every browser. Therefore I'd advise you to use the popular library FileSaver. The angular download file then becomes a one-liner:. If you don't like adding a dependency for this and would prefer to use the manual approach shown before, you might as well refactor the code for saving the blob into a separate service, angular download file.
You can also create a custom injection token for URL - also see angular download file how we'll do this for FileSaver. By setting the option observe to events while making an HTTP request, we won't just receive the final response body of the request but also get access to intermediate HTTP events. We also need to explicitly pass the option reportProgress in order to receive HttpProgressEvents. Our HTTP request will eventually look like follows:. Since we don't just want to forward these events to every component, our service has to do some more work.
Otherwise our component would have to deal with HTTP specifics - that's what services are for! Instead let's introduce a data structure representing a download with progress:. A Download angular download file be in one of three states, angular download file.
Either it hasn't started yet, therefore it's pending. Otherwise it's done or still in progress. We use TypeScript's union types to define the different download states. Additionally, a download has a number indicating the download progress from 1 to Once a download is done, it will contain a Blob as its content - until then this property is not available, therefore null. Now we want to abstract from specific HTTP events to our newly defined data structure.
This way our components can be decoupled from the underlying network protocol. Since we're dealing with multiple events coming in over time, a RxJS operator is well suited here - so let's create one! The first step for this will be the creation of type guards helping us to distinguish different HTTP events. This way we can access event-specific fields in a type-safe way. They both contain the discriminator field type allowing us to easily return a boolean for the type assertion in our guards.
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 scanan 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 HttpProgressEventwe calculate the progress based on the number of bytes already loaded and the angular download file 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 HttpResponsewe won't alter the download's state and return it as it is. This way, for example, we can keep the information in angular download file 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 :, angular download file. Notice that this download operator accepts an optional parameter saver. Once a HTTP response is received, angular download file, 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, angular download file. 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. Let's use the Progress Bar from Angular Material to show how far along our download is. The component now only has to assign an observable download to this property:. We can then subscribe to this observable through the AsyncPipe in combination with NgIf.
While the download is pending we'll display the progress bar in 'buffer' mode you may also use 'query'otherwise the progress is determinate. The bar's value can then easily be applied from Download. Pro Tip : If you need to map something to more than two values inside a template or rather a ternary statement won't do it for you: map the observable to the type you need or use a custom pipe instead of calling a component function from the template, angular download file.
Both methods are pretty easy to write, more declarative and perform better. Here's angular download file StackBlitz showing everything in action. The downloaded file is only 3MB, so you might want to enable throttling to see more of the progress bar. I hope this article helped you with your project, angular download file. Hire meif you need further support solving your specific problem.
Sometimes even just a quick code review or second opinion can make a great difference. Its a common desire: having something rotate or fly around to entertain the user while the moderately performing backend fishes data from angular download file knows where.
Though it seems easy to borrow a spinner angular download file CodePen and display it while you make the server…. Angular File Download with Progress March 10, web development frontend angular. DownloadProgress event. Essen, Germany. Loading Indication in Angular January 30, Its a common desire: having something rotate or fly around to entertain the user while the moderately performing backend fishes data from god knows where. Though it seems easy to borrow a spinner from CodePen and display it while you make the server… web development frontend angular.
File Download with Angular 7 PART 01
, time: 9:08Angular download file
blogger.com — This is a zip archive that contains all of the files released for this AngularJS version. Use this file to get everything in a single download. blogger.com — The core AngularJS framework. This is all you need to get your AngularJS app running. AngularJS is what HTML would have been, had it been designed for building web-apps. Declarative templates with data-binding, MVW, MVVM, MVC, dependency injection and great testability story all implemented with pure client-side JavaScript! The set of files included in each version directory are: blogger.com— This is a zip archive that contains all of the files released for this AngularJS Use this file to get everything in a single download. blogger.com— The core AngularJS framework.
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