Nativescript send camera capture to server

问题

In my Nativescript application I would like to capture an image using the camera module and then send the bytes directly to the server via http call.

Here is my code (incomplete for brevity):

var cameraModule = require("camera");
var http = require("http");
...

cameraModule.takePicture().then(function (img) {
  // how to extract the actual bytes from img???
  
  http.request({
    url: some_url,
    method: "POST",
    headers: { "Content-Type": "application/octet-stream" },
    content: ???
  });
});

Is there a way to do that?

I was looking at nativescript-background-http and it seems to fit my requirements exactly, but the example shows the file being loaded from a path only. I did not have any luck making this to work on iOS.

Any help is greatly appreciated.

Thank you.

回答1:

A couple things;

"img" is actually a image source.
At this point the built in HTTP module does not support direct binary transfers, so we need to convert it to something that can be sent over the wire. So base64 is a text representation that can support binary, and it is a common encoding/decoding method.
Since we already have it as a image source we just use the cool toBase64String ability which give us the Base 64 data.

So here is basically is how I would do it (tested under android).

var cameraModule = require('camera');

var some_url="http://somesite";
// img is a image source
cameraModule.takePicture().then(function (img) {
  // You can use "jpeg" or "png".   Apparently "png" doesn't work in some
  // cases on iOS.  
  var imageData = img.toBase64String("jpeg");

  http.request({
    url: some_url,
    method: "POST",
    headers: { "Content-Type": "application/base64" },
    content: imageData
  }).then(function() { 
    console.log("Woo Hoo, we sent our image up to the server!");
  }).catch(function(e) { 
    console.log("Uh oh, something went wrong", e);
  });
});

回答2:

There are a few ways to do this. If your backend can take a base64 string you can use the image-source class and manipulate the data. I'm on my phone or I'd mock up a sample. It really depends what you expect on the server to be honest but most options are possible with NativeScript using the image-source and ui/image component.

http://docs.nativescript.org/api-reference/classes/_image_source_.imagesource.html#tobase64string

Going from memory here but try this when you get the (IMG) back.

var data = img.tobase64string(); that should give you a base 64 string of the image.

Just found this awesome sample from another question https://stackoverflow.com/a/37815237/1893557 This will work to send the file after you save it locally and uses the background-http plugin.

来源：https://stackoverflow.com/questions/37932936/nativescript-send-camera-capture-to-server

标签

nativescript