Download the media files with node in Azure serverless

Pre-requisite for Node in Azure Serverless 

1. You have created a function with with name "download-files"
2. You have downloaded ffmpeg files (ffmpeg.exe) in "site -> wwwroot-> bin"
3. You have created a folder with name wav_to_mp3 "site -> wwwroot-> wav_to_mp3"

Source Code

//Download the Required module
const http = require('https');
const fs = require('fs');
//const childProcess = require('child_process');
const path = require('path');

//Define constants
const VIDEO_PATH = 'wav_to_mp3/';
const ffmpegLib='bin/ffmpeg';

module.exports =  function (context, req) {
    ////////////// params declaration
    let bodyData=req.body;
    let tourStreamName=bodyData.tour_stream_name;
    let videoUrls=bodyData.url;
    
    let filename='';
    let filenameSuccessLog={};
    let completedCounter=0;
    if (tourStreamName && videoUrls.length>0) {
        ////////////////////// ALL VIDEOS DOWNLOAD ////////////////////////////
        //const forLoop = async _ => {
         videoUrls.forEach(async (url) => {
              filename=path.basename(url); 
             // let videoDownload=VIDEO_PATH+filename;
                //full video url, filename, force download
                downloadFileAsync(url,filename,0).then(data=>{  
                   filenameSuccessLog[data.filename]=data.success;
                   completedCounter++;
                   if(videoUrls.length==completedCounter){
                       messageData(200,{success:1,'msg':'',result:filenameSuccessLog});
                   }                    
               }); 
          })
        //}    
         //forLoop();
        ////////////////////// ALL VIDEOS DOWNLOAD ////////////////////////////

    } else {
        messageData(200,{success:0,msg:"Parameter missing (tour_stream_name OR url)",'result':{}});
    }
    
    
    
    //for print the message
    function messageData(statusCode,message){
        context.res = {
            status: statusCode,
            body: message,
            headers: {
                'Content-Type': 'application/json'
            }
        };   
         context.done();
               
    } 
    
};



///////////////////////////// Other Functions ////////////////////////////////////
/**
 * @url: url of video
 * @destination: file with name download in wav_to_mp3
 * @forcedownload: 1 means download again even
 */
async function downloadFileAsync(url, destination,forcedownload) {
    return new Promise(function(resolve, reject) {
        let result={success:0,'msg':'',filename:destination};
        if (fs.existsSync(VIDEO_PATH+destination) && forcedownload==0) {
            result.success=1
            resolve(result);            
        }else{
            const file = fs.createWriteStream(VIDEO_PATH+destination);
            const request = http.get(url, (res) => {
              res.pipe(file);
            });
            request.once('error', (error) => 
              {
                  result.msg=error;
                  reject(result);
              }
            );
            file.once('finish', () => 
              {
                result.success=1
                resolve(result);
              }
            );             
        }
       
        
    })
}

///////////////////////////// Other Functions ////////////////////////////////////

URL: https://function-name.azurewebsites.net/api/download-files
Method: POST
Request:

{"tour_stream_name":"arun","url":["https://example.com/video/0_20190821064650782.mp4","https://example.com/video/tq_33038dev-GM-ma9kW-1106-26079.mp4"]}

Response:

{
    "success": 1,
    "msg": "",
    "result": {
        "tq_33038dev-GM-ma9kW-1106-26079.mp4": 1,
        "0_20190821064650782.mp4": 1
    }
}

Install FFMPEG in Azure Serverless Architecture

Create "Function" in "Function App" in Azure (If you have not created)

https://docs.microsoft.com/en-us/azure/azure-functions/functions-create-first-azure-function

Install FFMPEG in Azure Server

1. Now Go to Function App, and Click on the your "Function App"
2. Click on "Platform Features" then click on "Advance tools (Kudu)" like blow
   
   
3. In Kudu, select CMD from the Debug console menu.
   
   
4. Now, you can navigate to the folder by click on site -> wwwroot.
   
   
   
5. Create a folder with bin,here we will put the ffmpeg library.
6. a. Go to the https://ffmpeg.zeranoe.com/builds/ (for FFMPEG)
   b. Download the build as per Architecture.
   c. Unzip the downloaded content.
   d. Now copy the ffmpeg.exe, ffplay.exe and ffprobe.exe (from bin folder in downloaded).
   e. Copy these three files in site -> wwwroot-> bin folder.
   
7. Create a folder with wav_to_mp3,here we will store the media like photo, videos etc.
8. Here you can run the ffmpeg command such ffmpeg -version