Apache PDFBox - Split Pages

Operation Name

Apache PDFBox - Split PagessplitPages

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Description

Splits a PDF document into multiple smaller PDFs. You can:

• Split into individual pages, or
• Split in larger chunks using the pageIncrement parameter.

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Inputs

Parameter	Type	Required	Description
PDF File [Binary]	InputStream (Binary)	Required	The PDF document to be split.
Page Increment	Integer	Optional	How many pages per chunk. Default is 1 (split into single-page PDFs). Set to e.g. 3 to split every 3 pages into one part.

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Output

• Payload: List<InputStream> (List of binary streams) A list of split PDFs (each with pageIncrement number of pages, except the last chunk which may have fewer).
• Attributes: PdfBoxFileAttributes Metadata from the original file: number of pages, size, title, etc.

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MuleSoft Flow Example

<mule	xmlns="http://www.mulesoft.org/schema/mule/core"
	xmlns:doc="http://www.mulesoft.org/schema/mule/documentation"
	xmlns:pdfbox="http://www.mulesoft.org/schema/mule/pdfbox"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns:file="http://www.mulesoft.org/schema/mule/file"
	xsi:schemaLocation="http://www.mulesoft.org/schema/mule/core
	http://www.mulesoft.org/schema/mule/core/current/mule.xsd
	http://www.mulesoft.org/schema/mule/pdfbox
	http://www.mulesoft.org/schema/mule/pdfbox/current/mule-pdfbox.xsd
	http://www.mulesoft.org/schema/mule/file
	http://www.mulesoft.org/schema/mule/file/current/mule-file.xsd">

	<flow name="main">
		<scheduler doc:name="Scheduler" doc:id="dsgkfy" >
			<scheduling-strategy>
				<fixed-frequency timeUnit="HOURS"/>
			</scheduling-strategy>
		</scheduler>
		<flow-ref name="Apache PDFBox - Split Pages" />
	</flow>

	<sub-flow name="Apache PDFBox - Split Pages">
		<set-payload doc:id="vxsfk5" doc:name="Set payload" mimeType="application/octet-stream" value='#[%dw 2.0
output application/java
---readUrl("https://www.adobe.com/support/products/enterprise/knowledgecenter/media/c4611_sample_explain.pdf", "application/octet-stream") as Binary]'></set-payload>
		<pdfbox:split-pdf-by-increment doc:name="Apache PDFBox - Split Pages" doc:id="tcisia" pageIncrement="2"/>
		<logger doc:name="Logger" doc:id="ecdqs5s" message='#[%dw 2.0
output text
---
"\n\n Apache PDFBox - Split Pages"
++ "\n\n⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄"
++ "\n\nSplit Pages Attributes: " ++ (write(attributes, "application/json")) as String
++ "\n\nSplit Pages Payload: " ++ "Number of separate pdf Docs is " ++ (sizeOf(payload) as String)
++ "\n\n^^^^^^^^^^^^^^^^^^^^"
++ "\n\n Apache PDFBox - Split Pages"
++ "\n\n"]'/>
		<foreach doc:name="Foreach" doc:id="pjrtvx" batchSize="1">
			<file:write path='#["test" ++ (vars.counter as String) ++  ".pdf"]' doc:name="Write" doc:id="qjtqjy" />
		</foreach>
	</sub-flow>

</mule>

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Notes

• Default behavior (pageIncrement=1): Each output PDF will contain one page.
• Custom chunks (pageIncrement=3): Each output PDF will contain up to 3 pages.
• Last chunk: May contain fewer pages if the total doesn't divide evenly.
• Use case: Ideal for batch processing individual pages or creating multi-page segments.

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Underlying Application Interface

See Apache PDFBox JavaDoc

Pseudo Code

Operation: splitPdfByIncrement

Input:
  pdfFile: Binary content of the PDF (InputStream)
  pageIncrement: Number of pages per split document (Integer, Optional, defaults to 1)
  streamingHelper: MuleSoft StreamingHelper (for context/utilities)

Output:
  Result containing:
    - A List of InputStreams, each representing a split PDF document, as output.
    - PDF file attributes of the original document as attributes.

Errors:
  PDF_PROCESSING_ERROR: If the page increment is invalid or if saving a split document fails.
  PDF_LOAD_FAILED: If the original PDF document cannot be loaded (corrupt or invalid).
  PDF_METADATA_EXTRACTION_FAILED: If metadata cannot be retrieved from the original document.

Steps:
1. Validate the `pageIncrement`:
   - If `pageIncrement` is null or less than or equal to 0, throw a ModuleException with PDF_PROCESSING_ERROR.
2. Convert the input `pdfFile` InputStream to a byte array.
3. Get the size of the byte array (originalPdfSize).
4. Initialize an empty List to store the InputStreams of the split documents.
5. Initialize a variable for original PDF attributes (will be extracted later).
6. Try to load the original PDF document from the byte array using PDFBox Loader.
7. If loading fails, throw a ModuleException with PDF_LOAD_FAILED.
8. Try to extract metadata from the loaded original PDF document using the `extractPdfMetadata` helper.
   - If metadata extraction fails, throw a ModuleException with PDF_METADATA_EXTRACTION_FAILED.
9. Get the total number of pages from the original PDF document.
10. If the total number of pages is 0, log a warning and return an empty list of split documents with the extracted original attributes.
11. Create a new PDFBox Splitter instance.
12. Set the `splitAtPage` property of the Splitter to the `pageIncrement`.
13. Use the Splitter to split the original PDDocument into a List of new PDDocument objects.
14. Initialize a list to keep track of resources (split PDDocuments and ByteArrayOutputStreams) to close.
15. Iterate through each split PDDocument in the list returned by the Splitter:
    a. Add the current split PDDocument to the resources-to-close list.
    b. Create a new ByteArrayOutputStream.
    c. Add the ByteArrayOutputStream to the resources-to-close list.
    d. Try to save the current split PDDocument to the ByteArrayOutputStream.
    e. If saving fails, throw a ModuleException with PDF_PROCESSING_ERROR.
    f. Create a new ByteArrayInputStream from the ByteArrayOutputStream's content and add it to the list of split documents.
16. After processing all split documents, close all the split PDDocuments in the resources-to-close list. (Closing ByteArrayOutputStreams is generally a no-op and not strictly necessary here).
17. Log the number of split documents created and the page increment used.
18. Create a Result object containing:
    - The List of InputStreams (the split PDF contents) as the output.
    - The extracted original PDF file attributes as attributes.
19. Return the Result object.
20. Ensure the original loaded PDF document is closed properly in a finally block, even if errors occur during splitting or saving.

Methods used from the Apache PDFBox library

• org.apache.pdfbox.Loader.loadPDF(byte[] input): Used in Step 6 to load the original PDF document from the input byte array.
• org.apache.pdfbox.pdmodel.PDDocument.getDocumentInformation(): Used within the extractPdfMetadata helper (called in Step 8) to retrieve the metadata from the original document. Methods from the returned PDDocumentInformation object (like getTitle(), getAuthor(), etc.) are then used to populate the attributes.
• org.apache.pdfbox.pdmodel.PDDocument.getNumberOfPages(): Used in Step 9 to get the total number of pages in the original document.
• org.apache.pdfbox.multipdf.Splitter(): Used in Step 11 to create a new instance of the PDF splitter.
• org.apache.pdfbox.multipdf.Splitter.setSplitAtPage(int pageIncrement): Used in Step 12 to configure the splitter to split the document every pageIncrement pages.
• org.apache.pdfbox.multipdf.Splitter.split(PDDocument document): Used in Step 13 to perform the actual splitting of the original PDDocument into a list of new PDDocument objects.
• org.apache.pdfbox.pdmodel.PDDocument.save(OutputStream output): Used in Step 15d within the loop to save each individual split PDDocument to a ByteArrayOutputStream.
• org.apache.pdfbox.pdmodel.PDDocument.close(): Used in Step 16 to close each of the split PDDocuments after they have been saved, and also in Step 20 to ensure the original loaded PDDocument is closed.