Web Technology Experts Notes

Wednesday 25 September 2019

MongoDB indexing and Embed document

Question: How to create indexing on single column?

db.users.ensureIndex({"title":1})

1- Indexing in Ascending Order.

Question: How to create indexing on multiple column?

db.users.ensureIndex({"title":1,"description":-1})

1- Indexing in Ascending Order.
-1- Indexing in Descendig Order.

Question: How to make unique key in MongoDB?

db.users.ensureIndex({"username":1},{unique:true,sparse:true})

Now you can't add duplicate username in users collection.

Question: What is sparse in MongoDB indexing?
Sparse indexes only contain entries for documents that have the indexed field. The index skips over any document that is missing the indexed field. The index is sparse because it does not include all documents of a collection. .

Question: How to create indexing in background process?

db.users.ensureIndex({"title":1},{background:true})

Question: How to create indexing on column which can have duplicate values?

db.users.ensureIndex({"title":1},{dropDups:true})

Question: How can we set index name while creating indexing?

db.users.ensureIndex({"title":1},{name:'bankdb_users_index'})

Question: How to drop an index on single column?

db.users.dropIndex({"title":1})

Question: How to drop all indexes on document?

db.users.dropIndexex()

Question: How to update all index in collection?

db.collection.reIndex()

Question: How to create indexing in Embed document?

db.users.ensureIndex({"profile.city":1})

Search Document From Embed document

db.users.find( { "profile.city" : "newYork" } )

Question: Compare "Multiple collections" vs "Embedded documents"?

No much differences for insertion and updates document.
Separate collections are better when you need to select individual documents and gives more control over querying.
Embedded documents are better when embed document is less OR No More.
Getting record from embedded documents is easy as compare Multiple collections.
Embed document limit is 16MB

Question: What is Relationships in MongoDB?
Relationships denotes how various documents are logically related to each other.

Question: What are different ways to achieve the relationships in MongoDB?
Following are various two Approaches
1) Embedded Approaches 2) Referenced Approaches

Question: Given an example of Embedded?

[
  {
    "_id": ObjectId("52ffc33cd85242f436099901"),
    "contact": "987654321",
    "dob": "01-01-1991",
    "name": "Tom Benzamin",
    "address": [
      {
        "pincode": 123456,
        "city": "Los Angeles",
        "state": "California"
      },
      {       
        "pincode": 456789,
        "city": "Chicago",
        "state": "Illinois"
      }
    ]
  }
]

Question: Given an example of Referenced?

[
  {
    "_id": ObjectId("52ffc33cd85242f436099901"),
    "contact": "987654321",
    "dob": "01-01-1991",
    "name": "Tom Benzamin",
    "address": [
        ObjectId("63ffc4a5d85242602e000000"),
        ObjectId("63ffc4a5d85242602e000001")
    ]
  }
]

Sunday 22 September 2019

MongoDB Interview Question And Answers for 1 Year Experience

Question: How do I query mongodb with like ?
Following are few example of like as compare to SQL Query

/*select * from users where name like "%B%";*/
db.users.find({name: /B/});

/*select * from users where name like "B%"; */
db.users.find({name: /^B/});

/*select * from users where name like "%B"; */
db.users.find({name: /B$/});

Question: How to execute case in sensitive query?

/*select * from users where name like "%B%" OR like "%b%"; */
db.users.find({name: /b/i});

Question: How to list all collections in the mongoDB?
Following are three different methods.

db.getCollectionNames()

show collections

show tables

Question: Pretty print in MongoDB shell?
Normally we use query as below:

db.users.find()

For Pretty display, use like below:

db.users.find().pretty()

Question: How to get the last N records?

db.users.find().sort({_id:-1}).limit(20);
/* -1 means descending order */

Question: How to export collection into CSV?

mongoexport --host localhost --db bank --collection users --csv --out e:/dump/mycsv.csv --fields name,age,gender

Question: How to import into collection from CSV?

mongoimport -d bank -c users --type csv --file e:/dump/mycsv.csv --headerline

Question: How can I rename a field for all documents in MongoDB?

db.students.updateMany( {}, { $rename: { "name": "full_name" } } )

Question: How to store date/time in mongodb

db.users.insert({date: ISODate("2014-02-10T10:50:42.389Z")})

Thursday 19 September 2019

MongoDB Cursor with Examples

Question: What is cursor in MongoDB?
Cursor is a pointer to the result set of a query.
When you run a query for documents we retrieve a pointer (cursor) to the results instead of all result return.

Question: Give example of Cursor?

var myCursor=db.users.find({"age":30});
while (myCursor.hasNext()) {
   print(tojson(myCursor.next()));
}

Question: How to get the data type of variable?

var data=10;
typeof data;

var data='10';
typeof data;

Output

number
string

Question: What is use of forEach with Cursor?
Iterates the cursor to each document.
Example 1

db.users.find({"age":30}).forEach(printjson);

Example 2

db.users.find({"age":30}).forEach(function(data){
    print(data.name);
});

Output

name1
name2
name3

Question: How to use limit with Query?

 
db.users.find({"age":30}).limit(5).pretty();

Now, cursor will return maximum 5 records.

Question: How to get results in Array instead of JSON?

 
db.users.find({"age":30}).toArray()

Question: How to get number of results from Query?

 
db.users.find({"age":30}).size(); //2

Question: How to sort records by name in Ascending order?

 
 db.users.find({"age":30}).sort({"name":1}).forEach(function(data){print(data.name);});

Question: How to sort records by name in Descending order?

 
 db.users.find({"age":30}).sort({"name":-1}).forEach(function(data){print(data.name);});

Question: How to skip 4th record from query?

 
 db.users.find({"age":30}).skip(4).forEach(function(data){print(data.name);});

Question: How to search records with indexing?

 
 db.users.find({"age":30}).hint({"age":1}).pretty();

Wednesday 18 September 2019

What is sharding in MongoDB?

Question: What is sharding in MongoDB?
Sharding is a method for distributing data across multiple machines and its MongoDB's approach to meeting the demands of data growth. With increase of the size of the data, a single machine may not be sufficient to store the data OR read and write data. to fix this problem there are two different methods.
Vertical Scaling: Increase the capacity of single server and increase the power.

Powerful CPU
Increase RAM
Increase storage

Horizontal Scaling: dividing the system dataset and load over multiple servers.
We can use multiple server for storing and read/data data.
Using multiple server is lower cost than single machine with high-end hardware but increase the complexity in infrastructure and maintenance for the deployment.

Question: What are MongoDB Query Capabilities?

Sorting on one/multiple fields with ascending/descending order.
Projection (Retrieving only specified fields from each document in the cursor, not the entire document).
Cursor skip() and limit() to easily implement pagination.
explain() will return the detail on query will help to optimize the query.
aggregate() function used for grouping the records. db.users.aggregate([{$match:{gender:"male"}}, { $group: { _id: null, count: { $sum: 1 } } }]);
$match and $unbind function.

Question: How to database details?

db.stats();

Output

{
  "db": "bank",
  "collections": 4,
  "objects": 12,
  "avgObjSize": 245.33333333333334,
  "dataSize": 2944,
  "storageSize": 28672,
  "numExtents": 4,
  "indexes": 2,
  "indexSize": 16352,
  "fileSize": 67108864,
  "nsSizeMB": 16,
  "extentFreeList": {
    "num": 0,
    "totalSize": 0
  },
  "dataFileVersion": {
    "major": 4,
    "minor": 22
  },
  "ok": 1
}

Question: How to collection details?

db.users.stats();

Output

{
  "ns": "bank.users",
  "count": 5,
  "size": 2480,
  "avgObjSize": 496,
  "numExtents": 1,
  "storageSize": 8192,
  "lastExtentSize": 8192,
  "paddingFactor": 1,
  "paddingFactorNote": "paddingFactor is unused and unmaintained in 3.0. It remains hard coded to 1.0 for compatibility only.",
  "userFlags": 1,
  "capped": false,
  "nindexes": 1,
  "totalIndexSize": 8176,
  "indexSizes": {
    "_id_": 8176
  },
  "ok": 1
}

Monday 16 September 2019

Angularjs listing example with JSON


[script src="http://ajax.googleapis.com/ajax/libs/angularjs/1.4.8/angular.min.js"][/script]
[script src="http://ajax.googleapis.com/ajax/libs/angularjs/1.4.8/angular-animate.js"][/script]
[style]
    .secdsubmenu{position:absolute; right:22px; top:2px; border:1px solid #eee; background:#fff; z-index:99}
    .secdsubmenu ul {padding:10px; margin:0}
    .secdsubmenu ul li{list-style:none; font-size:13px; color:#333; padding:0; margin:0; white-space:nowrap; border-bottom:1px solid #eee; height:30px; line-height:30px; }
    .secdsubmenu ul li a{color:#333; text-decoration:none}
[/style]
<div ng-app="myAppName" ng-controller="myCtrl">
<div class="inputfield">
<input ng-model="$ctrl.query" placeholder="Search" type="text" />
    </div>
<table border="1" cellpadding="2" cellspacing="0" style="width: 500pxpx;">
        <tbody>
<tr>
            <th>Title <button ng-click="sortBy('Title')">&gt;</button></th>
            <th>Date &amp; Time</th>
            <th>Status</th>
            <th>Action</th>
        </tr>
<tr ng-repeat="x in names| filter:$ctrl.query |  orderBy:Title:reverse">
            <td>{{x.Title}}</td>
            <td>{{x.DateTime}}</td>
            <td>{{x.Status}}</td>

            <td><a href="https://www.blogger.com/blogger.g?blogID=5911253879674558037#" ng-click="mySubmenu = !mySubmenu">...</a>
                <br />
<div class="secdsubmenu" ng-show="mySubmenu">
<ul>
<li><a href="https://www.blogger.com/blogger.g?blogID=5911253879674558037#">Edit</a></li>
<li><a href="https://www.blogger.com/blogger.g?blogID=5911253879674558037#">Delete</a></li>
<li><a href="https://www.blogger.com/blogger.g?blogID=5911253879674558037#">View URL</a></li>
<li><a href="https://www.blogger.com/blogger.g?blogID=5911253879674558037#">Embeded Code</a></li>
</ul>
</div>
</td>
        </tr>
</tbody></table>
</div>
[script]
    var myApp = angular.module('myAppName', ['ngAnimate']);
    myApp.controller('myCtrl', function($scope, $http) {
        $http.get("load_data.php")
                .then(function(response) {
                    $scope.names = response.data.records;
                });
        $scope.mySubmenu = false;

        $scope.Title = 'title';
        $scope.reverse = true;

        $scope.sortBy = function(title) {
            $scope.reverse = ($scope.title === title) ? !$scope.reverse : false;
            $scope.title = title;
        };
    });
[/script]

JSON Data load_data.php

    
{ "records":[ 
{"Title":"Title 1","DateTime":"Jul 29 2016, 01:00 AM","Status":"Completed"}, 
{"Title":"Title 2","DateTime":"Jul 28 2016, 02:00 PM","Status":"Completed"}, 
{"Title":"Title 3","DateTime":"Jul 27 2016, 03:00 AM","Status":"Completed"}, 
{"Title":"Title 4","DateTime":"Jul 26 2016, 04:00 AM","Status":"Completed"}, 
{"Title":"Title 5","DateTime":"Jul 25 2016, 05:00 AM","Status":"Completed"}, 
{"Title":"Title 6","DateTime":"Jul 24 2016, 06:00 AM","Status":"Completed"}, 
{"Title":"Title 7","DateTime":"Jul 23 2016, 09:00 AM","Status":"Completed"},
]}

Thursday 12 September 2019

New PHP 7 Feature List

Question: Why we should use PHP 7 as compare to PHP5?

Improved performance. Its twice as fast as compare to PHP 5.
Lower Memory Consumption.
Scalar type declarations.
Return and Scalar Type Declarations.
Consistent 64-bit support
Many fatal errors converted to Exceptions
Secure random number generator.
Various old and unsupported SAPIs and extensions are removed from the latest version
NULL coalescing operator removed
Anonymous Classes Added.
Zero cost asserts
Use of new Zend Engine 3.0

Question: What is PHPNG?
PHPNG branch has been merged into master and has been used as the base for PHP 7.0.
PHPNG target is improve the performance and memory usage efficiency of PHP.

Question: What is a PHP parser?
PHP parser is a software which understand your coding and convert to computer language So that it can be executed & gives a output in HTML.

Question: What is a Scalar type declarations?
Allowing/prohibited datatype declaration in functions know for Scalar type declarations.
There are two options in Scalar type declarations
1) Coercive Mode (default)
2) Strict Mode

function sum(int ...$ints) {
      return array_sum($ints);
   }
   print(sum(2, '20', 4.2)); //26.2

Question: How to use return type declarations?

 function returnIntValue(int $value): int {
      return $value;
   }
   print(returnIntValue(5));

Question: What is spaceship operator?
It is Operator which is used to compare two expressions.
It return -1, 0 or 1.

print( 1 <=> 1); //0
print( 1 <=> 2); //-1
print( 2 <=> 1); //1

Question: Can define accept an array?
Yes, It can. For Example:

define('CLIENTS', [
    'client 1',
    'client 2',
    'client 3'
]);

Question: What is use of Closure::call() in PHP7?
It is used to temporarily bind an object scope to a closure and invoke it.
For Example:

 class A {
      private $x = 1;
   }
   $value = function() {
      return $this->x;
   };
   print($value->call(new A));

Question: How to import import Classes using single use statement?
Before PHP 7

use com\mytestclass\ClassA;
use com\mytestclass\ClassB;
use com\mytestclass\ClassC as C;

In PHP 7

 use com\mytestclass\{ClassA, ClassB, ClassC as C};

Question: What are Deprecated features in PHP7?
Following are deprecated feature in PHP7.

Old Style Constructure.

 class A {
      function A() {
         print('Deprecated');
      }
   }

Static calls to non-static methods.

class A {
      function b() {
         print('Deprecated');
      }
   }
   A::b();

password_hash() salt

Question: What extension are removed ?

ereg
mssql
mysql
sybase_ct

Question: From where I can download PHP7?
http://php.net/downloads.php

Question: How to setup PHP7 with WampServer?
http://www.wampserver.com/en/

Question: What is Class Abstraction?
1. Classes defined as abstract may not be instantiated.
2. Class that contains at least one abstract method must also be abstract.
3. When inheriting from an abstract class, all methods marked abstract in the parent's class declaration must be defined by the child.
4. if the abstract method is defined as protected, the function implementation must be defined as either protected or public, but not private.

Question: Tell me something about Interface?
We use "interface" keyword to create class.
All methods declared in an interface must be public.
To implement an interface, the implements operator is used.
We can include multiple interface while implementing

Question: What are Traits? Give example
Traits are a mechanism for code reuse in single inheritance languages such as PHP.
We can't create instance of a traits

We can create Traits as below:-

    trait Hello {
        public function sayHello() {
            echo 'Hello ';
        }
    }

We can use multiple traits using comma like below

use Hello, World;

When two traits have same function, it would conflict but we can fix using insteadof like below

A::bigTalk insteadof B;

We can set the visibility of function using "as" like below

use HelloWorld { sayHello as protected; }

We can use one trait from another using "use"
we can also define abstract,static, data members, method

Question: What is Overloading?
Overloading in PHP provides means to dynamically create properties and methods.
These dynamic entities are processed via magic methods one can establish in a class for various action types.

__get(), 
__set(), 
__isset() 
__unset() 
__call()
__callStatic()

Wednesday 11 September 2019

What is difference between Mongoexport and Mongodump

Question: What is mongodump ?
mongodump is a utility for creating a binary export of the contents of a database. mongodump is used for full backup, partial backup, syncing from production to staging/development, and changing the storage engine.

Question: What are popular options available with mongodump?
--help for Help
--version Version of mongodb
--host Host of database
--version Version of mongodump
--port Specify the port
--username Specify the username
--password Specify the password
--db Specify the database name
--collection Specify the collection name
--query Specify the query
--queryFile Specify the queryFile name
--gzip Compress the output
--out Specify the output folder
--repair Repair the database name

Question: Give few example of mongodump
Run Below command from Administrator window
Backup of all database?

 mongodump

Backup of Single database?

 mongodump --db bank

Backup of collection?

mongodump --db bank --collection users

How to repair the mongoDB?

mongod --dbpath  "c:/data/db" --repair

Question: What is mongoexport?
mongoexport is used to export the collections data to a JSON or CSV format.

Question: How to export collection using mongoexport?

mongoexport --db bank --collection users --out D:\mm\users.json

Question: How to export collection fields using mongoexport?

mongoexport --db bank --collection users --fields "age,gender,email" --out D:\mm\users_e.json

Question: How to export collection data on behalf of query?

mongoexport --db bank --collection users --query "{'age':'female'}" --out D:\mm\users_e.json

Tuesday 10 September 2019

MongoDB export and Import databases with Example

Following command will works from Administrator window.

Question: How to backup of all database?

 mongodump

Question: How to Restore databases

mongorestore

Question: How to backup of Single database?

 mongodump --db bank

Question: How to Restore single database

mongorestore --db bank dump/bank

Question: How to backup of collection?

mongodump --db bank --collection users

Question: How to Restore single database

mongorestore --db testdb --collection users dump/bank/users.bson

Question: How to repair the mongoDB?

mongod --dbpath  "c:/data/db" --repair

Monday 9 September 2019

How Azure functions can convert mp4 to mp3 with node using ffmpeg?

Pre-requisite

You have created a function with with name "convert-audio"
You have downloaded and uploaded ffmpeg files (ffmpeg.exe) in "site -> wwwroot-> bin"
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');
//Define constants
const VIDEO_PATH = 'wav_to_mp3/';
const ffmpegLib='bin/ffmpeg';

module.exports =  async function (context, req) {
    ////////////// params declaration
    let bodyData=req.body;
    let audioFile=bodyData.audio_file;
    let videoFile=bodyData.video_file;
    let extension=bodyData.extension;
    
    if (audioFile && videoFile && extension) {
        if(fs.existsSync(VIDEO_PATH+videoFile)){
            await ffmpegConvertVideoToAudio(VIDEO_PATH+videoFile,VIDEO_PATH+audioFile,extension).then(data=>{
                messageData(200,{success:1,'msg':'',result:{audio_file:data.filename}});
           });            
        }else{
            messageData(200,{success:0,msg:"video_file does not exist",'result':{}});
        }

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



///////////////////////////// Other Functions ////////////////////////////////////
function ffmpegConvertVideoToAudio(sourcefile, destinationFile, extension) {
    return new Promise(function(resolve, reject) {
        let result={success:0,'msg':'',filename:destinationFile};
        console.log('ffmpegConvertVideoToAudio called '+destinationFile);
          var args = [
              '-i', sourcefile,
              '-f', extension, destinationFile
          ];
          var proc = childProcess.spawnSync(ffmpegLib, args);   
            result.success=1
            resolve(result);   
    });

}    
///////////////////////////// Other Functions ////////////////////////////////////

URL: https://function-name.azurewebsites.net/api/convert-audio
Method: POST
Request: {"video_file":"0_20190821064650782.mp4","audio_file":"arun.mp3","extension":"mp3"} Response:

{
    "success": 1,
    "msg": "",
    "result": {
        "audio_file": "wav_to_mp3/arun.mp3"
    }
}

URL: https://function-name.azurewebsites.net/api/convert-audio
Method: POST
Request: {"video_file":"0_20190821064650782.mp4","audio_file":"arun.flac","extension":"flac"} Response:

{
    "success": 1,
    "msg": "",
    "result": {
        "audio_file": "wav_to_mp3/arun.flac"
    }
}

MongoDB update and delete records with examples

Question: How to Update Single Record? (Even Multiple Found)

db.players.update({"age":29},{$set:{number:1000}})

It will delete single record.
Output

WriteResult({"nMatched":1,"nUpserted":0,"nModified":1})

Question: How to update Update multiple Record? - 1 way

db.players.update({"age":29},{$set:{number:100}},{multi:true})

It will delete multiple record.
Output

WriteResult({
  "acknowledged": true,
  "matchedCount": 3,
  "modifiedCount": 3
})

Question: How to Update multiple Record? - 2 Way

db.players.updateMany({"age":29},{$set:{number:135}})

Output

WriteResult({
  "acknowledged": true,
  "matchedCount": 3,
  "modifiedCount": 3
})

Question: How to remove a Record(s)?

db.players.remove({"_id" : ObjectId("57ce95da8a12a77c41313adc")});

Will Delete all the record with matched condition.
Output

WriteResult({"nRemoved":1})

Question: How to remove a Record(s) with limit?

db.players.remove({"age":30},2);

It will deleted only 2 records.
Output

WriteResult({"nRemoved":2})

Sunday 8 September 2019

Mongodb index commands with examples

Create OR Use existing Database

use bank;

Create a new collection.

db.createCollection("users");

Add Records in collection.

db.users.insert([{"isActive":false,"balance":"$3,960.64","age":30,"eyeColor":"blue","name":"Dawn Keith","gender":"female","company":"COSMOSIS","email":"dawnkeith@cosmosis.com","phone":"+1 (839) 437-3421","address":"392 Clifford Place, Fontanelle, Arizona, 2687"},{"isActive":false,"balance":"$1,280.14","age":31,"eyeColor":"green","name":"Bettie Eaton","gender":"female","company":"COMTREK","email":"bettieeaton@comtrek.com","phone":"+1 (861) 460-2317","address":"203 Allen Avenue, Elrama, North Carolina, 4453"},{"isActive":true,"balance":"$2,042.37","age":38,"eyeColor":"green","name":"Margie Ayala","gender":"female","company":"VOIPA","email":"margieayala@voipa.com","phone":"+1 (941) 569-2231","address":"111 Schroeders Avenue, Suitland, Louisiana, 7042"},{"isActive":false,"balance":"$3,170.35","age":37,"eyeColor":"blue","name":"Baker Townsend","gender":"male","company":"EVIDENDS","email":"bakertownsend@evidends.com","phone":"+1 (808) 500-2793","address":"190 Just Court, Canoochee, Alabama, 325"}]);

Get all records

db.users.find().pretty();

Analyse the Query

db.users.find().explain("executionStats");

Add Index on collection

db.users.ensureIndex({"age":1});

Get all indexes on collection.

db.users.getIndexes();

Output

[
  {
    "v": 1,
    "key": {
      "_id": 1
    },
    "name": "_id_",
    "ns": "bank.users"
  },
  {
    "v": 1,
    "key": {
      "age": 1
    },
    "name": "age_1",
    "ns": "bank.users"
  }
]

Delete Index on collection.

db.users.dropIndex({"age":1});

Output

{
  "nIndexesWas": 2,
  "ok": 1
}

Drop all indexes.

db.users.dropIndexes();

Output

{
  "nIndexesWas": 1,
  "msg": "non-_id indexes dropped for collection",
  "ok": 1
}

Check Indexes, after droping an index.

db.users.getIndexes();

Output

[
  {
    "v": 1,
    "key": {
      "_id": 1
    },
    "name": "_id_",
    "ns": "bank.users"
  }
]

ReIndex the collecton.

db.users.reIndex()

Output

{
  "nIndexesWas": 1,
  "nIndexes": 1,
  "indexes": [
    {
      "key": {
        "_id": 1
      },
      "name": "_id_",
      "ns": "bank.users"
    }
  ],
  "ok": 1
}

Simple Aggregate Example

db.users.aggregate({$group:{_id:"$age",total:{$sum:1}}});

Output

{
  "_id": 37,
  "total": 1
}{
  "_id": 38,
  "total": 1
}{
  "_id": 31,
  "total": 1
}{
  "_id": 30,
  "total": 2
}

Average Aggregate Example

db.users.aggregate({$group:{_id:"$gender",avgAge:{$avg:"$age"}}});

Output

{
  "_id": "female",
  "avgAge": 32.25
}{
  "_id": "male",
  "avgAge": 37
}

Max Value in Aggregate

db.users.aggregate({$group:{_id:"$gender",richest:{$max:"$balance"}}});

Output

{
  "_id": "female",
  "richest": "$3,960.64"
}{
  "_id": "male",
  "richest": "$3,170.35"
}

Friday 6 September 2019

Download the media files with node in Azure serverless

Pre-requisite for Node in Azure Serverless

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

Now Go to Function App, and Click on the your "Function App"
Click on "Platform Features" then click on "Advance tools (Kudu)" like blow
In Kudu, select CMD from the Debug console menu.
Now, you can navigate to the folder by click on site -> wwwroot.
Create a folder with bin,here we will put the ffmpeg library.
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.
Create a folder with wav_to_mp3,here we will store the media like photo, videos etc.
Here you can run the ffmpeg command such ffmpeg -version

Saturday 31 August 2019

MongoDB operators with examples

Comparison Query Selectors

$eq  Equal to a specified value.
$gt  Greater than a specified value.
$gte  Greater than or equal to a specified value.
$lt  Less than a specified value.
$lte  Less than or equal to a specified value.
$ne  Not equal to a specified value.
$in  Matches any of the values specified in an array.
$nin  Matches none of the values specified in an array.

Example:

db.mycollectiontest.find('{"likes": {$gt:10}"likes"}');

Logical Query Selectors

$or  Joins query clauses with a logical OR Operator.
$and  Joins query clauses with a logical AND Operator.
$not  Inverts the effect of a query expression.
$nor  Joins query clauses with a logical NOR returns.

Example

db.mycollectiontest.find({"likes": {$gt:10}, $or: [{"by": "tutorials point"})

Element Query Selectors

$exists  Matches documents that have the specified field.
$type  Selects documents if a field is of the specified type.

Evalution Query Selector

$mod  Performs a modulo operation.
$regex  Specified regular expression.
$text  Performs text search.
$where  Matches documents that satisfy a JavaScript expression.

Array Query Selector

$all        Matches arrays that contain all elements specified in the query.
$elemMatch Selects documents if element in the array field matches all the specified $elemMatch conditions.
$size       Selects documents if the array field is a specified size.

Field Update Operators

$inc        Increments the value.
$mul        Multiplies the value.
$rename     Renames a field.
$setOnInsert Sets the value of a field if an update results in an insert of a document.
$set  Sets the value of a field in a document.
$unset  Removes the specified field from a document.
$min  Only updates the field if the specified value is less than the existing field value.
$max  Only updates the field if the specified value is greater than the existing field value.
$currentDate  Sets the value of a field to current date, either as a Date or a Timestamp.

Monday 19 August 2019

MongoDb PHP functions Questions and Answers

Question: How to connect to MongoDb with PHP?

$mongoObj = new MongoClient();

Question: How to select database?

$mongoDbObj = $mongoObj->mydb;

Question: How to create collection?

$collection = $mongoDbObj->createCollection("mycollectiontest");

Question: How to select collection?

$collection= $mongoDbObj->mycollectiontest;

Question: How to insert document in collection?

/* 1 document */
$document = array( 
      "title" => "MongoDB", 
      "description" => "MongoDB database", 
      "likes" => 100,
      "unlikes", 50
   );
   $collection->insert($document);
/* 2 document */
$document = array( 
      "title" => "MongoDB2", 
      "description" => "MongoDB database2", 
      "likes" => 1002,
      "unlikes", 502
   );
   $collection->insert($document);

Question: How to list all documents?

   $cursor = $collection->find();
   foreach ($cursor as $document) {
      print_r($document);
   }

Output

Array
(
    [_id] => MongoId Object
        (
            [$id] => 57c3e73d9ba8827012000029
        )

    [title] => MongoDB
    [description] => MongoDB database
    [likes] => 100
    [0] => unlikes
    [1] => 50
)
Array
(
    [_id] => MongoId Object
        (
            [$id] => 57c3e7e79ba8821815000029
        )

    [title] => MongoDB2
    [description] => MongoDB database2
    [likes] => 1002
    [0] => unlikes
    [1] => 502
)
Array
(
    [_id] => MongoId Object
        (
            [$id] => 57c3e8fb9ba882181500002a
        )

    [title] => MongoDB2
    [description] => MongoDB database2
    [likes] => 1002
    [0] => unlikes
    [1] => 502
)

Question: How to list all documents (2nd way)?

 $cursor = $mongoObj->mydb->{'mycollectiontest'}->find();
/*$mongoObj is clinet, mydb is database, mydb is collections*/
   foreach ($cursor as $document) {
      print_r($document);
   }

Question: How to list all documents (3rd way)?

$query = array('title' => 'MongoDB');
$cursor = $collection->find($query);
   foreach ($cursor as $document) {
      print_r($document);
   }

Question: How to delete a document?

 $collection->remove(array("title"=>"MongoDB2"));

Question: How to update a document?

  $collection->update(array("title"=>"MongoDB"), 
 array('$set'=>array("description"=>"This is updated description")));

Tuesday 13 August 2019

How do I add environment variables in Unix

Question: How to print the environment values?

printenv

env

Question: How to SET the environment values For Korn shell (KSH)?

var=value
export varname

Question: How to SET the environment values For Bourne shell (sh and bash)?

export var=value

Question: How to SET the environment values For C shell (csh or tcsh)?

setenv var value

Question: What is .bashrc?
.bashrc is a shell script that Bash runs whenever it is started interactively.

Question: Can we set the environment value in .bashrc?
Yes, you can set the value in this also. like below

export PATH="$PATH:/some/addition"

Sunday 4 August 2019

How to post raw data using CURL in Zend Framework 2

Question: How to post raw data using Zend?

        $client = new Client('http://example.com/ajax/get-feedback-status', array(
            'maxredirects' => 0,
            'timeout' => 30
        ));

        // Performing a POST request
        $client->setMethod('POST');
        //Set data
        $client->setParameterGet(array(
            'first_name' => 'Web',
            'middle_name' => 'Technology',
            'last_name' => 'Experts',
            'category' => 'notes',
        ));
        $response = $client->send();
        if ($response->isSuccess()) {
            // the POST was successful
            echo $response->getBody();
        } else {
            echo 'Request is failed';
        }

Question: Can we post Multi dimensional array in Zend?
Yes, See example below.

        $client = new Client('http://example.com/ajax/get-feedback-status', array(
            'maxredirects' => 0,
            'timeout' => 30
        ));

        // Performing a POST request
        $client->setMethod('POST');
        //Set data
        $client->setParameterGet(array(
            'first_name' => 'Web',
            'middle_name' => 'Technology',
            'last_name' => 'Experts',            
            'post-ids' => array(10, 20, 30)
        ));

Question: How to add Cookie in httpClient Object?

        $client = new Client('http://example.com/ajax/get-feedback-status', array(
            'maxredirects' => 0,
            'timeout' => 30
        ));
        $cookieString = \Zend\Http\Header\SetCookie::fromString('Set-Cookie: flavor=chocolate%20chips');
        $client->addCookie($cookieString);

Question: How to change the HTTPS transport layer in httpClient Request?

        $config = array(
            'adapter' => 'Zend\Http\Client\Adapter\Socket',
            'ssltransport' => 'tls'
        );

        $client = new Client('http://example.com/ajax/get-feedback-status', $config);
        $cookieString = \Zend\Http\Header\SetCookie::fromString('Set-Cookie: flavor=chocolate%20chips');
        $client->addCookie($cookieString);

Question: How to call curl From proxy server?

        $config = array(
            'adapter'    => 'Zend\Http\Client\Adapter\Proxy',
            'proxy_host' => 'ADD HERE POST',
            'proxy_port' => 8000,
            'proxy_user' => 'USERNAME',
            'proxy_pass' => 'PASSWORD'
        );

        $client = new Client('http://example.com/ajax/get-feedback-status', $config);
        
        $client->setMethod('GET');        
        
        $response = $client->send();
        
    if ($response->isSuccess()) {
            // the POST was successful
            echo $response->getBody();
        } else {
            echo 'Request is failed';
        }

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Friday 6 September 2019

Pre-requisite for Node in Azure Serverless

Source Code

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

Install FFMPEG in Azure Server

Saturday 31 August 2019

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