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HTTP Poller

The HTTP Poller data source in ArcGIS Velocity sends an HTTP request to the specified URL. This ingests data that can be retrieved in a web browser by browsing to the same URL.

Example

The following is an example use case for the data source:

A GIS analyst wants to load district polygons stored in a .csv file on a web server into Velocity.

Usage notes

Keep the following in mind when working with the data source:

  • After configuring source connection parameters, configure the input data to define the schema and the key parameters.

  • If using OAuth authentication the following apply:

    • The HTTP Poller source supports authentication using OAuth 2.0 for HTTP endpoints that follow the Client Credentials or Password grant types. These OAuth grant types follow a pattern that includes the configuration of an HTTP request to fetch an access token. These are in addition to the data request that is typically configured as part of any HTTP Poller source type.

    • During configuration of the access token request, you are prompted to identify the access token from the response from the OAuth authorization server.

    • When returning to the configuration of the data request, remember to use the $accessToken global variable to specify the usage of the access token. This is often in an Authorization custom header with the Bearer $accessToken value. $accessToken can also be used in the POST body and URL parameters, as well as in the URL (for example, https://<<company.domain>>/$accessToken/<<method>>?<<url params>>).

Parameters

The following are the parameters for the data source:

Parameter

Description

Data type

URL

The full URL to the externally accessible HTTP endpoint.

This parameter supports the $accessToken global variable.

String

HTTP method

Specifies the HTTP method used for the HTTP endpoint, either GET or POST.

If POST is chosen, you can specify a message body.

String

POST body

The message body to be included when sending a POST HTTP request.

This provides a selection between x-www-form-urlencoded and other generic text content types. It also sets the Content-type header.

This parameter only applies when the HTTP method parameter is set to POST.

This parameter supports the $accessToken global variable.

Authentication

Specifies the type of authentication used to access the HTTP endpoint. The options are None, Basic, Certificate, and OAuth.

String

Username

The username for accessing the HTTP endpoint.

This parameter only applies when the Authentication parameter is set to Basic.

String

Password

The password for accessing the HTTP endpoint.

This parameter only applies when the Authentication parameter is set to Basic.

Password

Certificate URL

The URL location of the client certificate for accessing the HTTP endpoint.

This parameter only applies when the Authentication parameter is set to Certificate.

String

Password

The client certificate password if one is set.

This parameter only applies when the Authentication parameter is set to Certificate.

Password

Custom headers

Optional custom headers to be included in the HTTP request that is sent to the specified HTTP endpoint.

For example, custom headers can be used to specify a third-party API key or authorization header.

This parameter supports analytic and $accessToken global variables.

Key-Value pair

URL parameters

Optional URL parameters to be included in the URL of the HTTP request that is sent to the specified HTTP endpoint.

While parameters can also be set in the URL parameter, the URL parameters entered here will override any matching parameter provided for the URL parameter.

Parameters defined here are always URL encoded.

This parameter supports analytic and $accessToken global variables.

Key-Value pair

Additional logging

(Optional)

Turn on the Additional logging parameter to specify whether you can log for raw HTTP requests and responses issued by Velocity.

Note:

Turn on this parameter for troubleshooting purposes and turn it off when troubleshooting is complete. Once turned on, start the feed; the debug level logs are available on the feed logs page. Contact Esri Technical Support for help with troubleshooting, if necessary.

Boolean

Considerations and limitations

Consider the following when using the data source:

  • When using OAuth authentication, the following apply:

    • Multiple requests to an authorization server and the associated data endpoint occur during authoring. Some APIs implement rate limiting for certain requests and this can affect authoring the feed.

    • For security reasons, the access token POST body must be reconfigured when editing the authentication parameters.

  • When a URL is specified for the HTTP Poller source and the connection attempt is unsuccessful, it is recommended that you review the Additional Details section in the error message. This information may include the raw request and response data, which can help diagnose and understand the cause of the failure.