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XML Parsing (From process or URL)

Advanced XML Handling in Web & App Handlers

The web-xml and app-xml handlers in DaFT provide advanced XML extraction and filtering capabilities, allowing users to:

  • Extract specific paths from deeply nested XML.
  • Select only certain fields from the extracted data.
  • Convert XML to JSON-like structures for consistent data handling.
  • Maintain full backward compatibility (default behavior is unchanged).

** How XML Path Extraction Works**

The xml_path option allows you to extract specific parts of an XML response using dot notation.

For example, given this XML response:

<response>
    <status>success</status>
    <data>
        <items>
            <item>
                <id>1</id>
                <name>Alice</name>
                <score>95</score>
            </item>
            <item>
                <id>2</id>
                <name>Bob</name>
                <score>88</score>
            </item>
        </items>
    </data>
</response>

You can extract only <data><items> using this configuration:

source = "https://api.example.com/data.xml"
type = "web-xml"
xml_path = "data.items.item"

Returned Output (Converted to JSON-like format):

[
    { "id": "1", "name": "Alice", "score": "95" },
    { "id": "2", "name": "Bob", "score": "88" }
]

** Field Filtering: Selecting Only the Data You Need**

The fields option allows you to extract only certain fields from the extracted data.

For example, with this configuration:

source = "https://api.example.com/data.xml"
type = "web-xml"
xml_path = "data.items.item"
fields = "id,name"

Returned Output:

[
    { "id": "1", "name": "Alice" },
    { "id": "2", "name": "Bob" }
]

** Handling Single XML Elements**

If the extracted xml_path points to a single XML element, it will be returned as an object instead of an array.

Example XML Response

<response>
    <metadata>
        <info>
            <version>1.0</version>
            <author>Admin</author>
        </info>
    </metadata>
</response>

Configuration

source = "https://api.example.com/data.xml"
type = "web-xml"
xml_path = "metadata.info"

Returned Output:

{
    "version": "1.0",
    "author": "Admin"
}

🛠 Using App XML Handler

The app-xml handler works exactly the same, but instead of fetching XML from a web URL, it runs a shell command that outputs XML.

Example Configuration

source = "/usr/local/bin/my-xml-app --option=value"
type = "app-xml"
xml_path = "response.results.item"
fields = "id,score"

Expected Output:

[
    { "id": "1", "score": "95" },
    { "id": "2", "score": "88" }
]

** What Happens If a Path Doesn’t Exist?**

If the specified xml_path does not exist in the response:

  • Instead of returning an error, it will return an empty array ([]).

If the specified fields don’t exist in the extracted data:

  • Those fields will be ignored without errors.

This ensures consistent behavior and prevents API failures due to missing XML elements.

** Backward Compatibility**

  • If you don’t use xml_path or fields, the handler works exactly as before.
  • No breaking changes for existing users!

For example, this configuration:

source = "https://api.example.com/data.xml"
type = "web-xml"

Will still return the entire XML response as a JSON-like array.

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