Issue

Pega Cloud does not support reading XML schema documents directly from file repository locations when validating XML with Parse XML rules. Schema documents must be read from the local file system, which is ephemeral on Pega Cloud and generally not advised.

Symptoms and Impact

XML schema validation fails when the schema document is configured using a file repository specification in the Schema URL field on the Parse XML rule form. In this case, validation fails with an error similar to the one shown below.

Error

Error Found: schema_reference.4: Failed to read schema document 'file://pegacloudrepository:/ImportClaimsCases/XSD/XSD_Lower/FNOL_XSD.xsd', because 1) could not find the document; 2) the document could not be read; 3) the root element of the document is not <xsd:schema>.

Root cause

During XML parser validation, if the schema file is stored in a file repository and the Schema URL value is similar to file://pegacloudrepository:/<directory path>, then Pega is unable to resolve it and the validation fails.

Solution

The following configuration steps allow a Parse XML to validate the XML being parsed against an XML Schema document. This approach leverages the local file system and has been confirmed to work in all the Pega Cloud environments.

1. Create a Text File record to hold the XML Schema document content

Select appropriate values for the Identifier and App Name key values. Set the File Type key value to xml. Use the Upload file button to upload the XML Schema file, and then save the record.

2. Create an Application Setting record for the XML Schema file URL

Select appropriate values for the Identifier and Owning Ruleset key values.

 

Category: <<blank>>

 

Value type: String/text

 

Value per production level: <<use the same file URL value for all production levels>>

 

Example for file URL

file:///usr/local/tomcat/xsd/AccountInquiry.xsd

 

3. Create a Function rule called FileExistsOnDisk

This function must be evaluated prior to applying the validating parse rule to ensure that the XML Schema file exists in the file location indicated by the Schema URL value on the Parse XML rule being applied. Add the function to an existing library or create a new one for this purpose.

Input parameters

 

 

Output

Java data type: boolean

 

Classification

Usage type: Condition Evaluation

 

Java

 

if (filePath.startsWith("file://")) {

  filePath = filePath.substring(7);

}

File file = new File(filePath);

return file.exists();

4. Create an Activity rule called WriteTextFileToDisk

This activity must be called prior to applying the validating parse rule if the FileExistsOnDisk function evaluates to False for the XML Schema file being used for validation.

Set the Applies To class for the activity to a class from which all of your Parse XML rules inherit, possibly @baseclass or Int-.

 

Parameters

 

 

 

Pages & Classes

 

 

Steps

1. Method: Obj-Open, Step page: TextFilePage

 

Method Parameters

 

 

Use a Jump to exit the activity if step status is not good.

 

2. Method: Java, Step page: TextFilePage

String filePath = tools.getParamValue("FilePath");

String fileSource = myStepPage.getString("pyFileSource");

byte[] fileBytes = fileSource.getBytes();

 

if (filePath.startsWith("file://")) {

  filePath = filePath.substring(7);

}

 

if (oLog.isDebugEnabled()) {

  oLog.debug("Writing " + fileBytes.length + " byte file '" + filePath + "' to disk");

}

 

try {

  java.nio.file.Path path = java.nio.file.Paths.get(filePath);

  java.nio.file.Files.createDirectories(path.getParent());

  java.nio.file.Files.write(path, fileBytes);

}

catch (Exception e) {

  throw new PRRuntimeException("Caught exception", e);

}

3. Method: Page-Remove, Step page: TextFilePage

5. Invoke WriteTextFileToDisk immediately before invoking Apply-Parse-XML

Add a step that conditionally writes the XML Schema file to disk before applying the parse rule.

 

Step details:

 

When

Enable conditions before this action: <<checked>>

 

Use @FileExistsOnDisk to check whether the XML Schema document needs to be written to disk.

 

Example

@FileExistsOnDisk(D_pxGetApplicationSettingValue[OwningRuleset:"XMLSchema",Purpose:" AccountInquiryXSDFilePath"].pySettingValue)

 

If true: Skip Step

If false: Continue Whens

 

Method

Call WriteTextFileToDisk

 

Pass current parameter page: <<unchecked>>

 

Pass the keys of the Text rule that holds the XML Schema document as method parameters and use the Application Setting for the local file path.

Example

 

Method Parameters

 

Step page

Same as the Apply-Parse-XML step

6. Modify the Parse XML rule Schema URL value

Set the Schema URL value on the XML tab to resolve the XML Schema file from the local file system. Use GRS syntax to look up the Application Setting that holds the file URL value.

 

Example

=D_pxGetApplicationSettingValue[OwningRuleset:"XMLSchema",Purpose:"AccountInquiryXSDFilePath"].pySettingValue