Pass Custom Headers

    Overview

    SIP headers (also called SIP fields) is a function of SIP. These headers help convey message attributes to ensure that information packets travel along the correct path when communicating between devices existing on separate networks. SIP headers are present for every HTTP request made by an outbound call and can be categorized into four main types: record route headers, route headers, via headers, and contact headers. Simply put, SIP headers are similar to HTTP header fields and always have the following format:

    <header_name>:<value>
    

    SIP headers are always prefixed with X-PH-. Only [A-Z], [a-z] and [0-9] characters are allowed for the SIP header key. Only [A-Z], [a-z], [0-9] characters are allowed for the SIP header value to ensure that you can encode this value in a URL. You may add multiple header fields by entering the value as a comma-separated list. For example:

    head1=val1,head2=val2,head3=val3,...,headN=valN
    

    If you are using a SIP endpoint and have configured your SIP phone to send custom SIP headers, then Plivo will send these SIP headers with your HTTP Request.

    Start your implementation with Plivo to pass custom SIP headers using PHLO or the traditional API/XML way. PHLO allows you to create and deploy the call flows using its intuitive canvas in few clicks. Refer to the instructions from the respective tabs below to start your integration with PHLO or XML as you wish.

    To make an outbound call with custom SIP headers, you can create and deploy a PHLO with a few clicks on the PHLO canvas. PHLO also lets you visually construct your entire use-case. With PHLO, you only pay for calls you make/receive, and building with PHLO is free.

    Outline

    Outbound- Call Flow

    Implementation

    In this section, we will guide you to create a PHLO to make an outbound call with custom SIP headers.

    Prerequisites

    1. Create a Plivo Account(if you don’t have one already): You can sign up with your work email address and complete the phone verification step using your mobile number.
    2. Set up your Dotnet dev environment: To set up your dev environment in your .NET(C#) programming language, please refer to the instructions available in the Set up Your Dotnet Dev Environment section.
    3. Buy a Plivo number(optional): You must have a voice-enabled Plivo phone number if you are willing to receive incoming calls. You can purchase numbers from the Numbers section of your Plivo Console. It is also possible to purchase numbers using the Numbers API.

    Create the PHLO

    You can create a PHLO by referring to the below instructions to make an outbound call with custom SIP headers:

    Create a PHLO for Outbound Calls with Custom SIP Headers

    • On the side navigation bar, click PHLO. The PHLO page will appear and display your existing PHLOs, if any. If this is your first PHLO, then the PHLO page will be empty.
    • Click Create New PHLO to build a new PHLO.
    • On the Choose your use-case window, click Build my own. The PHLO canvas will appear with the Start node.
      Note: The Start node is the starting point of any PHLO. You can choose between the four available trigger states of the Start node; Incoming SMS, Incoming Call, and API Request. For this PHLO, we will use the API Request trigger state.
    • From the list of components, on the left hand side, drag and drop the Initiate Call component onto the canvas. This will add a Initial Call node onto the canvas.
    • Connect the Start node with the Initiate Call node, using the API Request trigger state.
    • Configure the Initiate Call node with the caller ID using the From field. Enter the destination number you wish to call in the To field. Enter the custom SIP headers you wish to add in the Custom Headers field.
    • Once you have configured the node, click Validate to save the configurations.
    • Similarly, create a node for the Play Audio component and connect it to the Initiate Call node using the Answered trigger state.
    • Next, configure the Play Audio node to play a specific message to the user. For example, in this case, “Hello! you just received your first inbound call”.
    • Connect the Initiate Call node with the Play Audio node, using the Answered trigger state.
    • After you complete the configurations, provide a friendly name for your PHLO and click Save. Your PHLO is now ready. You can trigger the PHLO and test it out. For more information, refer to the following section.

    Set up Your PHP Dev Environment

    You must set up and install PHP and Plivo’s PHP SDK to make an outbound call with custom SIP headers. Here’s how.

    Install PHP

    Operating SystemInstructions
    OS XYou can install PHP using the official installer. You can also install it from here.
    LinuxTo install PHP on Linux you can find the instructions here.
    WindowsTo instll PHP on Windows you can use the official installer.

    Install Composer

    Composer is a dependency manager for PHP that is used in all modern PHP frameworks, such as Symfony and Laravel. We highly recommend using Composer as the package manager for your web project.

    1. Download the latest version of Composer.
    2. Run the following command in Terminal in order to run the composer:

       $ php ~/Downloads/composer.phar --version
      

      Note: PHAR (PHP archive) is an archive format for PHP that can be run on the command line

    3. Run the following command to make it executable:

       $ cp ~/Downloads/composer.phar /usr/local/bin/composer
       $ sudo chmod +x /usr/local/bin/composer
       $ Make sure you move the file to bin directory.
      
    4. To check if the path has /usr/local/bin, use

       $ echo $PATH
      

      If the path is different, use the following command to update the $PATH:

       $ export PATH = $PATH:/usr/local/bin
       $ source ~/.bash_profile
      

      Note: If your PATH doesn’t include /usr/local/bin directory, we recommend adding it so that you can access it globally.

    5. You can also check the version of Composer by running the following command:

       $ composer --version.       
      

    1. Run the following command:

       $ curl -sS https://getcomposer.org/installer | php
      
    2. Run the following command to make the composer.phar file as executable:

       $ chmod +x composer.phar
      

      Note: PHAR (PHP archive) is an archive format for PHP that can be run on the command line

    3. Run the following command to make Composer globally available for all system users:

       $ mv composer.phar /usr/local/bin/composer
      

    1. Download and run the Windows Installer for Composer.

      Note: Make sure to allow Windows Installer for Composer to make changes to your php.ini file.

    2. If you have any terminal windows open, close all instances and open a fresh terminal instance.
    3. Run the Composer command.

       $ composer -V
      

    Install Plivo PHP Package

    • Create a project directory, run the following command:

      $ mkdir myphpapp
      
    • Change the directory to our project directory in the command line:

      $ cd myphpapp
      
    • To install the stable release, run the following command in the project directory:

      $ composer require plivo/plivo-php
      
    • Alternatively, you can download this source and run

      $ composer install
      

    Trigger the PHLO

    Once you have created and setup your PHP dev envrironment, you can go to your Plivo Consolse and copy the PHLO_ID. You can integrate a PHLO into your application workflow by making an API request to trigger the PHLO with the required payload.

    With Static Payload

    You can choose to either configure the mandatory params required for a PHLO while creating the PHLO itself or, you can pass the params as payload while triggering the PHLO from your app.

    Note: When you configure the params while creating the PHLO, the values are hardcoded, and they act as static payload.

    With Static Payload

    Code

    Now, create a file called TriggerPhlo.php and paste the following code:

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    <?php
    require 'vendor/autoload.php';
    use Plivo\Resources\PHLO\PhloRestClient;
    use Plivo\Exceptions\PlivoRestException;
    $client = new PhloRestClient("YOUR_AUTH_ID", "YOUR_AUTH_TOKEN");
    
    $phlo = $client->phlo->get("YOUR_PHLO_ID");
    try {
        $response = $phlo->run();
        print_r($response);
    } catch (PlivoRestException $ex) {
        print_r($ex);
    }
    

    With Dynamic Payload

    To use dynamic values for the parameters, you can use the liquid templating params while creating the PHLO and pass the values while triggering the PHLO.

    With Dynamic Payload

    Code

    Now, create a file called TriggerPhlo.php and paste the following code:

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    <?php
    require 'vendor/autoload.php';
    use Plivo\Resources\PHLO\PhloRestClient;
    use Plivo\Exceptions\PlivoRestException;
    $client = new PhloRestClient("YOUR_AUTH_ID", "YOUR_AUTH_TOKEN");
    
    $phlo = $client->phlo->get("YOUR_PHLO_ID");
    try {
        $response = $phlo->run(["from" => "+14157778888", "to" => "+14157778889"]); // These are the fields entered in the PHLO console
        print_r($response);
    } catch (PlivoRestException $ex) {
        print_r($ex);
    }
    

    You can get your Auth_ID and Auth_token from your dashboard AUTHID

    You can find the PHLO_ID on the PHLO Listing page. PHLO Listing

    Test and Validate

    You can save the file and use the below command to run your code.

    $ php TriggerPhlo.php
    
    Note: If you are using a Plivo Trial account for this example, you can only make calls to phone numbers that have been verified with Plivo. Phone numbers can be verified at the Sandbox Numbers page.

    To make an outbound call with custom SIP headers in the traditional API/XML way, you can refer to the instructions in the below section to begin your implementation.

    Outline

    Custom SIP Headers- Call Flow

    Implementation

    In this section, we will show you how to add custom SIP headers. The following API enables you to make an outbound call(single destination) or a bulk outbound call to PSTN(s) or SIP endpoint(s).

    POST https://api.plivo.com/v1/Account/{auth_id}/Call/

    Prerequisites

    This section will guide you through how to use Plivo APIs to make voice calls from your application. First, let’s make sure you meet these prerequisites before we dive into the code.

    • Plivo Auth Id and Auth Token: You will find your Plivo Auth Id and Auth Token on the home screen of your Plivo Console. Click here to sign-up for a Plivo account if you haven’t already!

      credentials

    • Plivo Phone Number(Optional): You can purchase numbers from the Numbers section of your Plivo Console and use the same as the caller ID for the outbound call. This number will also help you receive incoming calls as you must have a voice-enabled Plivo phone number to do the same. Please note that you can also purchase numbers using the Numbers API.

      Buy New Number

    • Answer Url: When a call is answered by the destination_number, you can control the call flow with the help of the answer_url set in the API request. Plivo will invoke the answer_url specified as soon as the call is answered and expect a valid XML response with instructions to handle the call. For example, you can use https://s3.amazonaws.com/static.plivo.com/answer.xml as answer_url to test your first outgoing call. The XML response of this is:

      <Response> 
      <Speak>Congratulations! You've made your first outbound call!</Speak> 
      </Response>
      

      As you can tell, the XML above holds instructions to say ‘Congratulations! You’ve made your first outbound call!’ to the callee. You can find the entire list of Plivo XML verbs and their details in the XML Reference section of the website here.

    Set up Your PHP Dev Environment

    You must set up and install PHP and Plivo’s PHP SDK to make an outbound call with Custom SIP headers. Here’s how.

    Install PHP

    Operating SystemInstructions
    OS XYou can install PHP using the official installer. You can also install it from here.
    LinuxTo install PHP on Linux you can find the instructions here.
    WindowsTo instll PHP on Windows you can use the official installer.

    Install Composer

    Composer is a dependency manager for PHP that is used in all modern PHP frameworks, such as Symfony and Laravel. We highly recommend using Composer as the package manager for your web project.

    1. Download the latest version of Composer.
    2. Run the following command in Terminal in order to run the composer:

       $ php ~/Downloads/composer.phar --version
      

      Note: PHAR (PHP archive) is an archive format for PHP that can be run on the command line

    3. Run the following command to make it executable:

       $ cp ~/Downloads/composer.phar /usr/local/bin/composer
       $ sudo chmod +x /usr/local/bin/composer
       $ Make sure you move the file to bin directory.
      
    4. To check if the path has /usr/local/bin, use

       $ echo $PATH
      

      If the path is different, use the following command to update the $PATH:

       $ export PATH = $PATH:/usr/local/bin
       $ source ~/.bash_profile
      

      Note: If your PATH doesn’t include /usr/local/bin directory, we recommend adding it so that you can access it globally.

    5. You can also check the version of Composer by running the following command:

       $ composer --version.       
      

    1. Run the following command:

       $ curl -sS https://getcomposer.org/installer | php
      
    2. Run the following command to make the composer.phar file as executable:

       $ chmod +x composer.phar
      

      Note: PHAR (PHP archive) is an archive format for PHP that can be run on the command line

    3. Run the following command to make Composer globally available for all system users:

       $ mv composer.phar /usr/local/bin/composer
      

    1. Download and run the Windows Installer for Composer.

      Note: Make sure to allow Windows Installer for Composer to make changes to your php.ini file.

    2. If you have any terminal windows open, close all instances and open a fresh terminal instance.
    3. Run the Composer command.

       $ composer -V
      

    Install Plivo PHP Package

    • Create a project directory, run the following command:

      $ mkdir myphpapp
      
    • Change the directory to our project directory in the command line:

      $ cd myphpapp
      
    • To install the stable release, run the following command in the project directory:

      $ composer require plivo/plivo-php
      
    • Alternatively, you can download this source and run

      $ composer install
      

    Create the Outbound Call App with Custom SIP Headers

    Once you have the above prerequisites set, You can follow the below instructions to create an app to make an outbound call with custom SIP headers and leave a text-to-speech message once the call recipient answers the call.

    Now, create a file called MakeCall.php and paste the following code:

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    <?php
    require 'vendor/autoload.php';
    use Plivo\RestClient;
    use Plivo\Exceptions\PlivoRestException;
    $client = new RestClient("YOUR_AUTH_ID", "YOUR_AUTH_TOKEN");
    try {
        $response = $client->calls->create(
            'the_callerID',
            ['the_destination_number'],
            'http://s3.amazonaws.com/static.plivo.com/answer.xml',
            'GET',
            [
                'ring_url' => 'http://WWW.RING.URL',
                'sip_headers' => 'Test=Sample',
            ]
        );
        print_r($response);
    }
    catch (PlivoRestException $ex) {
        print_r($ex);
    }
    
    Note:
    • Replace the placeholders auth_id & auth_token with your credentials from yourPlivo Console.
    • We recommend that you store your credentials in the auth_id & auth_token environment variables, so as to avoid the possibility of accidentally committing them to source control. If you do this, you can initialize the client with no arguments and it will automatically fetch them from the environment variables
    • You can use $_ENV or putenv/getenv function to store environment variables and fetch them while initializing the client.
    • Replace the placeholder the_callerID with the Phone number which you have purchased and the_destination_number with the phone number you will be making calls to.
    • Both the_callerID and the_destination_number should be in E.164 format, for example +15671234567.

    Test and Validate

    Once you have created the Outbound Call App with custom SIP headers, You can save the file and use the below command to run your code.

    $ php MakeCall.php
    
    Note: If you are using a Plivo Trial account for this example, you can only make calls to phone numbers that have been verified with Plivo. Phone numbers can be verified at the Sandbox Numbers page.

    Sample Response

    (201, {
            u'message': u'call fired',
            u'request_uuid': u'85b1d45d-bc12-47f5-89c7-ae4a2c5d5713',
            u'api_id': u'ad0e27a8-9008-11e4-b932-22000ac50fac'
        }
    )
    

    The SIP header can be seen as a query parameter in the answer_url

    /answer.xml?Direction=outbound&From=1111111111&ALegUUID=5260e820-958c-11e4-b6bf-498d468c930b&BillRate=0.00300&
    To=sip%3Aabcd150105094929%40phone.plivo.com&<mark>X-PH-Test=Sample</mark>&CallUUID=5260e820-958c-11e4-b6bf-498d468c930b&ALegRequestUUID=2202d0ab-a890-4199-8582-e7a2615cb23b&
    RequestUUID=2202d0ab-a890-4199-8582-e7a2615cb23b&SIP-H-To=%3Csip%3Aabcd150105094929%40phone.plivo.com%3E%3Btag%3D6U9J4.uVHI7KyEKSgD8vrPnAKQoR2QXc&
    CallStatus=in-progress&Event=StartApp
    

    Common Use Cases for Custom SIP Headers

    You can use custom SIP headers in use-cases where you wish to pass information from your frontend app to the backend app and vice versa. For example, when you want to send custom parameters from your frontend app such as customer ID, product information, etc. You can make use of the custom SIP headers and share such information from your frontend app to the backend app.