Search & Redact Text in a PDF using Swift for iOS

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//
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//  Copyright © 2018-2025 PSPDFKit GmbH. All rights reserved.
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//
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//  The Nutrient sample applications are licensed with a modified BSD license.
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//  Please see License for details. This notice may not be removed from this file.
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//
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import PSPDFKit
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import PSPDFKitUI
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class SearchAndRedactTextExample: Example {
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    override init() {
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        super.init()
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        title = "Search and Redact Text"
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        contentDescription = "Shows how to search and redact text."
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        category = .documentProcessing
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        priority = 15
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    }
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    override func invoke(with delegate: ExampleRunnerDelegate) -> UIViewController? {
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        let redactionPrompt = UIAlertController(title: "Search and Redact Text", message: "Enter a word to redact:", preferredStyle: .alert)
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        redactionPrompt.addTextField { textField in
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            textField.text = "Nutrient"
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        }
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        redactionPrompt.addAction(UIAlertAction(title: "Redact", style: .default) { [weak redactionPrompt] _ in
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            let wordToRedact = redactionPrompt?.textFields?.first?.text!
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            let document = AssetLoader.document(for: .welcome)
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            let status = StatusHUDItem.indeterminateProgress(withText: "Processing...")
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            status.push(animated: true, on: delegate.currentViewController?.view.window)
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            // Loop through all the pages of the document to find the search term.
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            // In production we recommend doing this on a utility queue.
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            // Note: The search is case sensitive.
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            for pageIndex in 0..<document.pageCount {
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                if let textParser = document.textParserForPage(at: pageIndex) {
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                    textParser.words.forEach { word in
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                        // Redact all the words that contain the search term.
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                        if word.stringValue.range(of: wordToRedact!) != nil {
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                            let redaction = self.createRedactionAnnotationFor(word: word, pageIndex: pageIndex)
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                            document.add(annotations: [redaction])
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                        }
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                    }
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                }
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            }
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            DispatchQueue.global(qos: .default).async {
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                // Use Processor to create the newly redacted document.
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                let processorConfiguration = Processor.Configuration(document: document)!
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                processorConfiguration.applyRedactions()
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                let redactedDocumentURL = FileHelper.temporaryPDFFileURL(prefix: "redacted")
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                let processor = Processor(configuration: processorConfiguration, securityOptions: nil)
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                try? processor.write(toFileURL: redactedDocumentURL)
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                DispatchQueue.main.async {
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                    status.pop(animated: true)
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                    // Instantiate the redacted document and present it.
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                    let redactedDocument = Document(url: redactedDocumentURL)
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                    let pdfController = PDFViewController(document: redactedDocument)
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                    delegate.currentViewController!.navigationController?.pushViewController(pdfController, animated: true)
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                }
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            }
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        })
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        redactionPrompt.addAction(UIAlertAction(title: "Cancel", style: .cancel))
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        delegate.currentViewController!.present(redactionPrompt, animated: true)
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        return nil
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    }
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    // MARK: Private
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    private func createRedactionAnnotationFor(word: Word, pageIndex: PageIndex) -> RedactionAnnotation {
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        let redactionRect = word.frame
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        let redaction = RedactionAnnotation()
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        redaction.boundingBox = redactionRect
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        redaction.rects = [redactionRect]
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        redaction.color = .orange
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        redaction.fillColor = .black
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        redaction.overlayText = "REDACTED"
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        redaction.pageIndex = pageIndex
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        return redaction
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    }
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}