January 11, 2016 12:58 pm

Getting a camera picture and saving it with PHP and Vanilla JavaScript 1/2

To show how to get a camera photo with the HTML5 User Media API and save it on our server we will build an app in which the users would be able to share their camera and take a snapshot. Upon doing this, the snapshot will be saved to the server and all user snapshots will be shown directly on the page.Getting a camera picture and saving it as a file with PHP and Vanilla JavaScript

The pictures below show how the app works.

scrshot1

scrshot2

The front-end

Firstly, we have some div elements with Twitter Bootstrap classes attached to them:

The div with a class of user-images is where all the saved images will be rendered. The div with the id of user-video is where the video stream will be shown so that the user can pick the right moment to take a photo. The snapshot id is where the actual image that was sent to the server will be shown. Upon refreshing the page, that image would show with the rest of the images in the user-images div.

The JavaScript

First we issue an Ajax request to a text file which would contain the path of each saved image separated by a new line. When we get the response, we convert it to an array of paths, loop over each path and add an image whose src attribute points to the path to the div destined for the user images.

Thereafter, we set up two variables – recording and mediaStream. The first will be used to know if the video stream should be started or if the image needs to be send to the back-end while the second will contain a global copy of the streamed media so that we can stop the media when the user takes his snapshot. Thereafter, we listen to click events on the green Take The Snapshot button

If the video is not being recorded yet (and the green button is clicked) we create a property to hold a reference to the user media. Notice that because the user media API is still experimental we attempt to see if the new User Media API is available (available at navigator.mediaDevices.getUserMedia) and use it in that case. If it is not available, we check if any of the prefixed versions of the old User Media API are available. We have confirmed that our usage of getUserMedia or mediaDevices.getUserMedia works in recent versions of Chrome and Firefox as of 19th December 2015. In the new API, we use promises with then (takes a function to be called when the asynchronous function is completed) and catch (takes a function to execute in case of an error) methods.

As to the old API, if any of the prefixed alternatives of the API exist, the first match will be saved to our navigator.theUserMedia property. Otherwise, null would be assigned to it. If the method is truthy, we call it, requesting only the user’s video input by passing an object with options. The second argument is the callback that will be called if the user allows us to use the desired input.

Therefore, if the user allows us, we create a video, add it to the page’s DOM, start it, and save the stream in a global variable in the onUserStream function. If he does not give us access (third argument to navigator.theUserMedia – a callback) or if he does not support the API – we just give him an alert.

Get Free source code in our 2nd part of this tutorial.

Author Ivan Dimov

Ivan is a student of IT, a freelance web designer/developer and a tech writer. He deals with both front-end and back-end stuff. Whenever he is not in front of an Internet-enabled device he is probably reading a book or traveling. You can find more about him at: http://www.dimoff.biz. facebook, twitter


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