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Java WkHtmlToPdf Wrapper Build Release

A Java based wrapper for the wkhtmltopdf command line tool. As the name implies, it uses WebKit to convert HTML documents to PDFs.

Requirements

wkhtmltopdf must be installed and working on your system.

Wrapper project dependency

Make sure you have Java Wrapper dependency added to your project.

If you are using Gradle/Maven, see example below:

Gradle

In your build.gradle:

dependencies {
    compile 'com.github.jhonnymertz:java-wkhtmltopdf-wrapper:1.3.1-RELEASE'
}

Maven

In your pom.xml:

<dependency>
    <groupId>com.github.jhonnymertz</groupId>
    <artifactId>java-wkhtmltopdf-wrapper</artifactId>
    <version>1.3.1-RELEASE</version>
</dependency>

Usage and Examples

// Attempt to find the wkhtmltopdf command from OS path
String executable = WrapperConfig.findExecutable();

// Initialize with the command wrapper
// Customize the OS command to be called if needed
Pdf pdf = new Pdf(new WrapperConfig(executable));

// Add global params:
pdf.addParam(new Param("--no-footer-line"), new Param("--header-html", "file:///header.html"));
pdf.addParam(new Param("--enable-javascript"));
pdf.addParam(new Param("--javascript-delay", "2000"));

// Add pages
Page page1 = pdf.addPageFromString("<html><head><meta charset=\"utf-8\"></head><h1>Müller</h1></html>");
Page page2 = pdf.addPageFromUrl("http://www.google.com");

// Add per-page params
page1.addParam(new Param("--footer-center", "Page1Footer"));
page1.addParam(new Param("--exclude-from-outline"));
page2.addParam(new Param( "--header-center", "Page2HeaderOverride"));

// Add a Table of Contents and ToC params
TableOfContents toc = pdf.addToc();
toc.addParam(new Param("--footer-center", "TocFooter"));
toc.addParam(new Param("--xsl-style-sheet", "my_toc.xsl"));

// Save the PDF
pdf.saveAs("output.pdf");

wkhtmltopdf location and automatic retrieval attempt

Library provides a method to attempt to find the wkhtmltopdf executable from the OS path, or an exact location can be provided:

// Attempt to find the wkhtmltopdf command from OS path
String executable = WrapperConfig.findExecutable();

// Exact custom location
String executable = "/usr/local/bin/wkhtmltopdf";

final Pdf pdf = new Pdf(new WrapperConfig(executable));

Note: make sure the tool wkhtmltopdf is installed and in the OS path for the user currently running the Java application. Otherwise, library will not be able to find the wkhtmltopdf. To test if the command is visible, you may try which wkhtmltopdf (linux) or where wkhtmltopdf (windows) in the command line.

Global params vs. per-object params

wkhtmltopdf accepts different types of options such as global, page, headers and footers, and toc. Please see wkhtmltopdf -H for a full explanation. The library allows setting params globally and per-object, as follows.

final Pdf pdf = new Pdf(new WrapperConfig(WrapperConfig.findExecutable()));

// Adding global params
pdf.addParam(new Param("--header-center", "GlobalHeader"));

// Adding per-object params
TableOfContents toc = pdf.addToc();
toc.addParam(new Param("--footer-center", "TocFooter"));

Page page1 = pdf.addPageFromString("<html><head><meta charset=\"utf-8\"></head><h1>Page1</h1></html>");
page1.addParam(new Param("--footer-center", "Page1Footer"));
page1.addParam(new Param("--exclude-from-outline")); // removes from toc

Page page2 = pdf.addPageFromUrl("http://www.google.com");
page2.addParam(new Param( "--header-center", "Page2HeaderOverride")); // override global header

Page/object ordering and ToC positioning

The list of pages/objects in the document appear as the order in which pages/objects were added to the main pdf. Except by the ToC, which is always placed at the beginning of the document. However, you can change this by using the setAlwaysPutTocFirst(false).

final Pdf pdf = new Pdf(new WrapperConfig(WrapperConfig.findExecutable()));

pdf.addCoverFromString("<html><head><meta charset=\"utf-8\"></head><h1>CoverPage</h1></html>");
pdf.addPageFromString("<html><head><meta charset=\"utf-8\"></head><h2>Page 1</h2></html>");
pdf.addToc(); // ToC will be placed at the beginning of the document by default, regardless of the order of addition
pdf.addPageFromString("<html><head><meta charset=\"utf-8\"></head><h2>Page 2</h2></html>");

pdf.getPDF(); // ToC forced to go first, then in order of addition: cover, page 1 and page 2

Changing ToC position

By default, the ToC is always placed at the beginning of the document. You can change this by using the setAlwaysPutTocFirst(false):

final WrapperConfig config = new WrapperConfig(WrapperConfig.findExecutable());
config.setAlwaysPutTocFirst(false);
final Pdf pdf = new Pdf(config);

pdf.addCoverFromString("<html><head><meta charset=\"utf-8\"></head><h1>CoverPage</h1></html>");
pdf.addPageFromString("<html><head><meta charset=\"utf-8\"></head><h2>Page 1</h2></html>");
pdf.addToc(); // ToC will be placed according to the order of addition as config.setAlwaysPutTocFirst(false) is set
pdf.addPageFromString("<html><head><meta charset=\"utf-8\"></head><h2>Page 2</h2></html>");

pdf.getPDF(); // Follows order of addition: cover, page 1, ToC, and page 2

Xvfb Support

XvfbConfig xc = new XvfbConfig();
xc.addParams(new Param("--auto-servernum"), new Param("--server-num=1"));

WrapperConfig wc = new WrapperConfig(WrapperConfig.findExecutable());
wc.setXvfbConfig(xc);

Pdf pdf = new Pdf(wc);
pdf.addPageFromUrl("http://www.google.com");

pdf.saveAs("output.pdf");

wkhtmltopdf exit codes

wkhtmltopdf may return non-zero exit codes to denote warnings, you can now set the Pdf object to allow this:

Pdf pdf = new Pdf();
pdf.addPageFromUrl("http://www.google.com");

pdf.setAllowMissingAssets();
// or:  
pdf.setSuccessValues(Arrays.asList(0, 1));

pdf.saveAs("output.pdf");

Timeouts

There are often situations in which the wkhtmltopdf may take longer to generate the file. By default, the library uses a 10 seconds timeout for all the internal processes depending on wkhtmltopdf. However, in some situation 10s may not be sufficient, thus you can customize this value:

Pdf pdf = new Pdf();
pdf.addPageFromUrl("http://www.google.com");

pdf.setTimeout(30); // 30 seconds timeout

pdf.saveAs("output.pdf");

Cleaning up temporary files

After the PDF generation, the library automatically cleans up the temporary files created. However, there may be situations in which the Pdf object is created but no PDF is generated. To avoid increasing the temp folder size and having problems, you can force the deletion of all temporary files created by the library by:

Pdf pdf = new Pdf();
pdf.cleanAllTempFiles();

This is not an official Wkhtmltopdf product

This library is not an official Wkhtmltopdf product. Support is available on a best-effort basis via github issue tracking. Pull requests are welcomed.

Known issues

Output of wkhtmltopdf is being added to resulting pdf (Issue #19)

  • Starting from 1.1.10-RELEASE version, there is a method saveAsDirect(String path), which executes wkhtmltopdf passing the path as output for wkhtmltopdf, instead of the standard input -. This saves the results directly to the specified file path without handling it with internal stdout.

Processes taking longer due to some wkhtmltopdf parameters, such as window.status, possibly resulting in timeouts (Pull #131)

  • Some parameters may cause wkhtmltopdf think that the page has not loaded and it will wait for longer, causing some internal processes of the library to be blocked. To avoid blocking the internal processes of the library, the given timeout (default 10s) was forcibly set to all the internal processes. This value can be increased by using setTimeout(int seconds). Please refer to the Timeouts section for more information.
  • This issue is often caused by developers unfamiliar with wkhtmltopdf features and not related to the library itself. If you are experiencing something related, check the command being generated and the parameters you are using. Try to remove them one by one to find the one causing the issue.

Because this library relies on wkhtmltopdf, it does not support concurrent PDF generations.

License

This project is available under MIT Licence.