How to set returned Image Data as ng-src of image in AngularJS

问题

I've got two ASP.Net Core methods at the moment - one tied to an API call, and one tied to a client-side Razor helper.

They're both located in my HomeController.cs.

API:

Here's the API call:

[HttpGet("api/GetImage")]
public async Task<ActionResult> ImageFromPath()
{
    RestClient client = new RestClient("http://IPADDRESS/cgi-bin/snapshot.cgi?channel=0");
    RestRequest request = new RestRequest(Method.GET);
    request.AddHeader("cache-control", "no-cache");
    request.AddHeader("authorization", "Basic aYu7GI");
    TaskCompletionSource<IRestResponse> taskCompletion = new TaskCompletionSource<IRestResponse>();

    RestRequestAsyncHandle handle = client.ExecuteAsync(request, r => taskCompletion.SetResult(r));
    RestResponse response = (RestResponse)(await taskCompletion.Task);

    return File(response.RawBytes, "image/png");
}

Razor:

Here's the Razor helper:

public async Task<ActionResult> ImageFromPath()
{
    RestClient client = new RestClient("http://IPADDRESS/cgi-bin/snapshot.cgi?channel=0");
    RestRequest request = new RestRequest(Method.GET);
    request.AddHeader("cache-control", "no-cache");
    request.AddHeader("authorization", "Basic aYu7GI");
    TaskCompletionSource<IRestResponse> taskCompletion = new TaskCompletionSource<IRestResponse>();

    RestRequestAsyncHandle handle = client.ExecuteAsync(request, r => taskCompletion.SetResult(r));
    RestResponse response = (RestResponse)(await taskCompletion.Task);

    return File(response.RawBytes, "image/png");
}

As you can see, the method bodies above are exactly the same. One simply has the HttpGet annotation.

---

Yet, when paired with their client-side handlers, they produce different results.

API:

Client-side handler for API call:

<img ng-src="{{imageSrc}}">

$http.get('/api/GetImage', { headers: { 'Accept': 'image/webp,image/apng,image/*,*/*;q=0.8' } }).then(function (response) {
    $scope.imageSrc = response.data;
});

Razor:

Client-side handler for Razor helper:

<img src="@Url.Action("ImageFromPath")" id="img2" />

---

Here's where the results show:

API:

Here's the API call preview in Network tab:

Razor:

Here's the Razor Helper call preview in Network tab:

API:

Here's the API call headers in Network tab:

Razor:

Here's the Razor Helper call headers in Network tab:

API:

---

Why does the Razor helper actually produce/return an image, yet the API call doesn't? How could I make the API call return an image just like the Razor helper does?

回答1:

You need few things. First, you should not access DOM directly inside Angular Controller.

<script src="http://ajax.googleapis.com/ajax/libs/angularjs/1.5.3/angular.js"></script>
<script src="http://ajax.googleapis.com/ajax/libs/angularjs/1.5.3/angular-animate.js"></script>
<script src="http://angular-ui.github.io/bootstrap/ui-bootstrap-tpls-1.3.2.js"></script>
<div ng-app="app">
    <my-content></my-content>
</div>
<script type="text/javascript">
    angular.module('app', []);

    angular.module('app')
        .component('myContent', {
            template: '<h1>{{$ctrl.title}}</h1><img src="{{$ctrl.imageSrc}}" />',
            controller: function ($http) {
                var self = this;
                self.title = "Title";
                // Just to verify image work
                //self.imageSrc = "https://i.stack.imgur.com/hM8Ah.jpg?s=48&g=1";
                $http.get('/Home/ImageFromPath').then(function (response) {
                    console.log(response.data);
                    self.imageSrc = response.data;
                });
            }
        });
</script>

Second, you will need to return based64 encoded string.

using System;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using RestSharp;

namespace DemoWebCore.Controllers
{
    public class HomeController : Controller
    {
        public async Task<IActionResult> ImageFromPath()
        {
            RestClient client = new RestClient("https://i.stack.imgur.com/hM8Ah.jpg?s=48&g=1");
            RestRequest request = new RestRequest(Method.GET);
            request.AddHeader("cache-control", "no-cache");
            request.AddHeader("authorization", "Basic aYu7GI");
            TaskCompletionSource<IRestResponse> taskCompletion = new TaskCompletionSource<IRestResponse>();
            RestRequestAsyncHandle handle = client.ExecuteAsync(request, r => taskCompletion.SetResult(r));
            RestResponse response = (RestResponse)await taskCompletion.Task;
            return Ok("data:image/png;base64," + Convert.ToBase64String(response.RawBytes));
        }
    }
}

来源：https://stackoverflow.com/questions/45066586/how-to-set-returned-image-data-as-ng-src-of-image-in-angularjs