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Merged
asturio merged 3 commits into from
May 4, 2026
+305 −43
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Feature/output stream support for html to pdf batch utils #1539

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597c220
feature: add OutputStream support to HtmlToPdfBatchUtils
Julius1st May 1, 2026
cf5c7d6
feature: add OutputStream support to HtmlToPdfBatchUtils - Tests
Julius1st May 2, 2026
8522ad1
Merge branch 'master' into feature/OutputStream_support_for_HtmlToPdf…
asturio May 4, 2026
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188 changes: 145 additions & 43 deletions openpdf-html/src/main/java/org/openpdf/html/HtmlToPdfBatchUtils.java
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Original file line number Diff line number Diff line change
Expand Up @@ -54,6 +54,7 @@

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
Expand Down Expand Up @@ -92,27 +93,27 @@
*
* <h4>Convert a single HTML string to PDF</h4>
* <pre>{@code
* Path pdf = Html2PdfBatchUtils.renderHtmlString(
* Path pdf = HtmlToPdfBatchUtils.renderHtmlString(
* "<html><body>Hello World</body></html>",
* "https://example.com/",
* Path.of("out.pdf"),
* Html2PdfBatchUtils.CSS_A4_20MM,
* Html2PdfBatchUtils.setDpi(150)
* HtmlToPdfBatchUtils.CSS_A4_20MM,
* HtmlToPdfBatchUtils.setDpi(150)
* );
* }</pre>
*
* <h4>Batch convert multiple HTML files</h4>
* <pre>{@code
* List<HtmlFileJob> jobs = List.of(
* new HtmlFileJob(Path.of("file1.html"), Path.of("."), Path.of("file1.pdf"),
* Optional.of(Html2PdfBatchUtils.CSS_LETTER_HALF_IN),
* Optional.of(HtmlToPdfBatchUtils.CSS_LETTER_HALF_IN),
* Optional.empty()),
* new HtmlFileJob(Path.of("file2.html"), Path.of("."), Path.of("file2.pdf"),
* Optional.empty(),
* Optional.of(Html2PdfBatchUtils.registerFontDir(Path.of("fonts"))))
* Optional.of(HtmlToPdfBatchUtils.registerFontDir(Path.of("fonts"))))
* );
*
* BatchResult<Path> result = Html2PdfBatchUtils.batchHtmlFiles(jobs,
* BatchResult<Path> result = HtmlToPdfBatchUtils.batchHtmlFiles(jobs,
* path -> System.out.println("Created PDF: " + path),
* error -> error.printStackTrace()
* );
Expand All @@ -124,6 +125,9 @@
* <li>Always provide a {@code baseUri} (or {@code baseDir}) if your HTML references relative resources.</li>
* <li>Use {@code rendererCustomizer} to adjust advanced rendering settings like DPI or font loading.</li>
* <li>Batch methods allow optional success and failure callbacks for real-time feedback during processing.</li>
* <li>When using OutputStream-based batch jobs, every job <em>must</em> use a distinct
* {@code OutputStream} instance. Sharing a stream between concurrent jobs will corrupt
* the output. The caller is responsible for closing streams after the batch completes.</li>
* </ul>
*
* @implNote Internally uses {@link Executors#newVirtualThreadPerTaskExecutor()} for efficient parallelism.
Expand Down Expand Up @@ -153,6 +157,42 @@ public record UrlJob(String url, Path output,
Optional<String> injectCss,
Optional<Consumer<ITextRenderer>> rendererCustomizer) {}

/**
* Render raw HTML string to a pre-opened {@link OutputStream}.
*
* <p><strong>Concurrency note:</strong> Each job in a batch runs on its own virtual thread.
* Every job in the batch <em>must</em> use a distinct {@code OutputStream} instance —
* sharing a stream between jobs will corrupt the output. The caller is responsible
* for closing the stream after the batch completes.</p>
*/
public record HtmlStringStreamJob(String html, String baseUri, OutputStream outputStream,
Optional<String> injectCss,
Optional<Consumer<ITextRenderer>> rendererCustomizer) {}

/**
* Render an HTML file (and its relative assets) to a pre-opened {@link OutputStream}.
*
* <p><strong>Concurrency note:</strong> Each job in a batch runs on its own virtual thread.
* Every job in the batch <em>must</em> use a distinct {@code OutputStream} instance —
* sharing a stream between jobs will corrupt the output. The caller is responsible
* for closing the stream after the batch completes.</p>
*/
public record HtmlFileStreamJob(Path htmlFile, Path baseDir, OutputStream outputStream,
Optional<String> injectCss,
Optional<Consumer<ITextRenderer>> rendererCustomizer) {}

/**
* Render a remote URL to a pre-opened {@link OutputStream}.
*
* <p><strong>Concurrency note:</strong> Each job in a batch runs on its own virtual thread.
* Every job in the batch <em>must</em> use a distinct {@code OutputStream} instance —
* sharing a stream between jobs will corrupt the output. The caller is responsible
* for closing the stream after the batch completes.</p>
*/
public record UrlStreamJob(String url, OutputStream outputStream,
Optional<String> injectCss,
Optional<Consumer<ITextRenderer>> rendererCustomizer) {}

// ------------------------- Single operations -------------------------

/** Render an HTML string. */
Expand All @@ -163,29 +203,39 @@ public static Path renderHtmlString(String html, String baseUri, Path output,
Objects.requireNonNull(output, "output");
Files.createDirectories(output.getParent());

try (var out = new FileOutputStream(output.toFile())) {
renderHtmlString(html, baseUri, out, injectCss, rendererCustomizer);
}
return output;
}

/** Render an HTML string. */
public static void renderHtmlString(String html, String baseUri, OutputStream outputStream,
String injectCss,
Consumer<ITextRenderer> rendererCustomizer) {
Objects.requireNonNull(html, "html");
Objects.requireNonNull(outputStream, "output");

String finalHtml = injectCss != null && !injectCss.isEmpty()
? injectCssBlock(injectCss).apply(html)
: html;

try (var out = new FileOutputStream(output.toFile())) {
ITextRenderer renderer = new ITextRenderer();
SharedContext sc = renderer.getSharedContext();
// Slightly safer resource loading if you need custom schemes:
sc.setUserAgentCallback(renderer.getOutputDevice().getSharedContext().getUserAgentCallback());
ITextRenderer renderer = new ITextRenderer();
SharedContext sc = renderer.getSharedContext();
// Slightly safer resource loading if you need custom schemes:
sc.setUserAgentCallback(renderer.getOutputDevice().getSharedContext().getUserAgentCallback());

if (rendererCustomizer != null) {
rendererCustomizer.accept(renderer);
}
if (rendererCustomizer != null) {
rendererCustomizer.accept(renderer);
}

if (baseUri != null && !baseUri.isBlank()) {
renderer.setDocumentFromString(finalHtml, baseUri);
} else {
renderer.setDocumentFromString(finalHtml);
}
renderer.layout();
renderer.createPDF(out, true);
if (baseUri != null && !baseUri.isBlank()) {
renderer.setDocumentFromString(finalHtml, baseUri);
} else {
renderer.setDocumentFromString(finalHtml);
}
return output;
renderer.layout();
renderer.createPDF(outputStream, true);
}

/** Render an HTML file (and relatives). */
Expand All @@ -201,38 +251,57 @@ public static Path renderHtmlFile(Path htmlFile, Path baseDir, Path output,
return renderHtmlString(html, base, output, injectCss, rendererCustomizer);
}

/** Render an HTML file (and relatives). */
public static void renderHtmlFile(Path htmlFile, Path baseDir, OutputStream outputStream,
String injectCss,
Consumer<ITextRenderer> rendererCustomizer) throws IOException {
Objects.requireNonNull(htmlFile, "htmlFile");
Objects.requireNonNull(outputStream, "output");

String html = Files.readString(htmlFile, StandardCharsets.UTF_8);
String base = (baseDir != null ? baseDir.toUri().toString() : htmlFile.getParent().toUri().toString());
renderHtmlString(html, base, outputStream, injectCss, rendererCustomizer);
}

/** Render a URL to PDF. */
public static Path renderUrl(String url, Path output,
String injectCss,
Consumer<ITextRenderer> rendererCustomizer) throws IOException {
Objects.requireNonNull(url, "url");
Objects.requireNonNull(output, "output");
Files.createDirectories(output.getParent());

try (var out = new FileOutputStream(output.toFile())) {
ITextRenderer renderer = new ITextRenderer();
if (rendererCustomizer != null) {
rendererCustomizer.accept(renderer);
}
renderUrl(url, out, injectCss, rendererCustomizer);
}
return output;
}

if (injectCss == null || injectCss.isEmpty()) {
// No CSS injection: load DOM directly via user agent and set base URL
org.w3c.dom.Document doc = renderer.getSharedContext().getUac().getXMLResource(url).getDocument();
renderer.setDocument(doc, url);
} else {
// Inject CSS: fetch HTML as text, prepend <style> to <head>, and set with base URL
String html;
try (var in = java.net.URI.create(url).toURL().openStream()) {
html = new String(in.readAllBytes(), java.nio.charset.StandardCharsets.UTF_8);
}
String finalHtml = injectCssBlock(injectCss).apply(html);
renderer.setDocumentFromString(finalHtml, url);
}
/** Render a URL to PDF. */
public static void renderUrl(String url, OutputStream outputStream,
String injectCss,
Consumer<ITextRenderer> rendererCustomizer) throws IOException {
Objects.requireNonNull(url, "url");
Objects.requireNonNull(outputStream, "outputStream");

renderer.layout();
renderer.createPDF(out, true);
ITextRenderer renderer = new ITextRenderer();
if (rendererCustomizer != null) {
rendererCustomizer.accept(renderer);
}
return output;

if (injectCss == null || injectCss.isEmpty()) {
org.w3c.dom.Document doc = renderer.getSharedContext().getUac().getXMLResource(url).getDocument();
renderer.setDocument(doc, url);
} else {
String html;
try (var in = java.net.URI.create(url).toURL().openStream()) {
html = new String(in.readAllBytes(), java.nio.charset.StandardCharsets.UTF_8);
}
String finalHtml = injectCssBlock(injectCss).apply(html);
renderer.setDocumentFromString(finalHtml, url);
}

renderer.layout();
renderer.createPDF(outputStream, true);
}

// ------------------------- Batch operations -------------------------
Expand Down Expand Up @@ -265,6 +334,39 @@ public static BatchResult<Path> batchUrls(List<UrlJob> jobs,
).toList(), onSuccess, onFailure);
}

public static BatchResult<Void> batchHtmlStringsToStreams(List<HtmlStringStreamJob> jobs,
Consumer<Void> onSuccess,
Consumer<Throwable> onFailure) {
return PdfBatch.run(jobs.stream().map(j -> (Callable<Void>) () -> {
renderHtmlString(j.html, j.baseUri, j.outputStream,
j.injectCss.orElse(null),
j.rendererCustomizer.orElse(null));
return null;
}).toList(), onSuccess, onFailure);
}

public static BatchResult<Void> batchHtmlFilesToStreams(List<HtmlFileStreamJob> jobs,
Consumer<Void> onSuccess,
Consumer<Throwable> onFailure) {
return PdfBatch.run(jobs.stream().map(j -> (Callable<Void>) () -> {
renderHtmlFile(j.htmlFile, j.baseDir, j.outputStream,
j.injectCss.orElse(null),
j.rendererCustomizer.orElse(null));
return null;
}).toList(), onSuccess, onFailure);
}

public static BatchResult<Void> batchUrlsToStreams(List<UrlStreamJob> jobs,
Consumer<Void> onSuccess,
Consumer<Throwable> onFailure) {
return PdfBatch.run(jobs.stream().map(j -> (Callable<Void>) () -> {
renderUrl(j.url, j.outputStream,
j.injectCss.orElse(null),
j.rendererCustomizer.orElse(null));
return null;
}).toList(), onSuccess, onFailure);
}

// ------------------------- Helpers -------------------------

/**
Expand Down
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