IPWorks Cloud 2020 Delphi Edition

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DoCustomOp Method

Executes an arbitrary WebHDFS operation.

procedure DoCustomOp(HttpMethod: String; RequestPath: String; Op: String);

Remarks

This method can be used to execute any WebHDFS operation the component does not explicitly implement.

Valid values for HttpMethod are:

  • GET (default if empty)
  • POST
  • PUT
  • DELETE

RequestPath must either be a valid resource path, or empty string. Op must be a valid WebHDFS operation (refer to the Hadoop WebHDFS documentation for a full list of supported operations).

Usage

When this method is called, the component will do the following:

  1. Build a request URL using URL, RequestPath, Op, and the query parameters held by the QueryParam* properties.
  2. Send the request using the given HttpMethod, the request URL built in step 1, the headers held by OtherHeaders, and the currently-configured authentication (if any; refer to AuthMechanism for more information). The request is always sent with an empty body.
  3. Store the response headers in the ParsedHeader* properties, and the response body in the stream specified using SetDownloadStream, the specified LocalFile, or ResourceData (using the same logic as DownloadFile).

If the response body is JSON data, the XPath, XText, and other X* configuration settings can then be used to navigate and extract information from it.

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IPWorks Cloud 2020 Delphi Edition - Version 20.0 [Build 8265]