# API Webhook Subscription
Two [**GET** operations ](#get-all-webhook-subscriptions)and three [**POST** operations](#post-operations) are present under Webhook Subscription. These are the API for the client to consume and subscribe to the webhooks.
## GET Operations
* [Get All Webhook Subscriptions](#get-all-webhook-subscriptions-2) - use this to get a list of all available webhooks you can subscribe to.
* [Get Webhook Subscriptions ](#get-webhook-subscription-1)- use this to get more details for a single kind of subscription.
### Get All Webhook Subscriptions
Path /WebHookSubscription/GetAllWebhookSubscriptions
* Type: GET
* Function: Returns a list of all Webhook Subscriptions
* No parameters required
* Expected Response – list of subscriptions in the following format:
```
[
{
"GUID": "00000000-0000-0000-0000-000000000000",
"Webhook": "PacketCreated",
"FilterObjectGUID": "00000000-0000-0000-0000-000000000000",
"FilterObjectType": "None",
"SubscriberURL": "string",
"Signature": "string",
"CustomHeader": "string",
"CustomHeaderValue": "string"
}
]
```
### Get Webhook Subscription
Path: /WebHookSubscription/GetWebhookSubscription
* Type: GET
* Function: Returns detail of a specific Webhook Subscription
* Parameter to set: webhookSubscriptionGUID
* Parameter values: GUID value present in GUID column of tblWebhookSubscriptions table.
Expected Response – a single subscription in the following format:
```
[
{
"GUID": "00000000-0000-0000-0000-000000000000",
"Webhook": "PacketCreated",
"FilterObjectGUID": "00000000-0000-0000-0000-000000000000",
"FilterObjectType": "None",
"SubscriberURL": "string",
"Signature": "string",
"CustomHeader": "string",
"CustomHeaderValue": "string"
}
]
```
Response Code: 200 :
Expected Response in case of invalid GUID: \
Response Code:400 - Bad Request \
The response should contain the below message: \
‘The request is invalid’ Request:
## POST Operations
* [Subscribe to Webhook](#subscribe-to-webhook-api) - use this to subscribe to an individual webhook.
* [Update Webhook Subscription](#update-webhook-subcription) - use this to update an existing subscription to an individual webhook
* [Unsubscribe ](#delete-webhook-subscription)- use this to permanently delete an existing subscription for an individual webhook.
### Subscribe to Webhook API
Path: /WebHookSubscription/SubscribeToWebhook
* Type: POST
* Function: Used to create a new subscription and the API returns the details of newly created
* Webhook Subscription
* Parameters:
```
{
"Webhook": "PacketCreated",
"FilterObjectGUID": "00000000-0000-0000-0000-000000000000",
"FilterObjectType": "None",
"SubscriberURL": "string",
"CustomHeader": "string",
"CustomHeaderValue": "string"
}
```
Expected Response: \
Response Code:200 \
Expected Response – subscription data in the following format:
```
[
{
"GUID": "00000000-0000-0000-0000-000000000000",
"Webhook": "PacketCreated",
"FilterObjectGUID": "00000000-0000-0000-0000-000000000000",
"FilterObjectType": "None",
"SubscriberURL": "string",
"Signature": "string",
"CustomHeader": "string",
"CustomHeaderValue": "string"
}
]
```
{% hint style="info" %}
Note: The subscriber URL is the address of the client that will receive the webhook messages. We can use to get the subscriber URL.
{% endhint %}
The signature should be added by the server when the subscription is created and then included in the webhook messages which are sent out.
### Update Webhook Subcription
Parameters and response as for [SubscribeToWebhook](#subscribe-to-webhook-api) plus the GUID of the WebHookSubscription to update
### Unsubscribe (Delete Webhook Subscription)
* Takes a Webhook subscription GUID as the only parameter.
* Permanently deletes a subscription from the database.
## API: Webhook Test-Simulate Event
A GET API called Simulate Event is present under Webhook Test.
* Parameter: any valid webHookSubscriptionGUID
* Creates a test WebHook message for a provided webHookSubscriptionGUID
## General API Validations
### Authorization
When an unauthorized request is sent, the APIs need to show a message stating ‘Authorization has been denied for this request’. Below is the response in case of an unauthorised request:
Quick steps to vaidate authorization:
1. Open the Swagger UI
2. Do not login to the test instance
3. Send a request with all the valid details
4. API throws an error saying Authorization has been denied
5. Login to the test instance
6. Retry the same request
7. API returns successful response as the request is authorized.
### Invalid Requests
When an invalid request is submitted, the APIs need to return 400-Bad Request Error and display a message stating, ‘The request is invalid’. Below is the response in case of invalid requests:
General scenarios where bad request error is seen are mentioned below:
* Wrong/Incorrect GUID values
* Syntax errors in the Request json
* Non existing values