A .NET wrapper for the wkhtmltopdf library with an object-oriented API.
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Latest commit b060dab Jan 29, 2016 @tuespetre Update README.md

README.md

TuesPechkin

TuesPechkin is a .NET Wrapper for the wkhtmltopdf library.

Things to know

Supported usage

wkhtmltox.dll

The wkhtmltox.dll file and any dependencies it might have (for older versions, 0.11.0-) are not included in the TuesPechkin NuGet package; however, you can bring your own copy of the library or download one of the following NuGet packages that contain the library:

  • TuesPechkin.Wkhtmltox.Win32
  • TuesPechkin.Wkhtmltox.Win64

You must have Visual C++ 2013 runtime installed to use these packages. Otherwise, you will need to download the MingW build of wkhtmltopdf and its dependencies from their website and use that with the library.

Reporting issues

If something doesn't seem right with your converted document, try converting with wkhtmltopdf directly. If you still have the problem, then you will need to take your issue to wkhtmltopdf's issues. Any issues related to visual problems like this will be closed unless the reporter can show that the problem is unique to this library.

Please follow similar guidelines as StackOverflow -- that is, provide any contextual information that you can about your application to help solve the issue.

Submitting pull requests

For 2.0.0 I am wanting to use the 'git flow' style of branching/merging/releasing. If you have a hotfix, please branch off of hotfix. If you are adding something, please branch off of develop. I won't fully re-explain the methodology here.

Usage

The API drastically changed once more for 2.0.0 for the sake of modularity and extensibility. Please read the following sections thoroughly.

1. Choose a deployment

TuesPechkin exposes an 'IDeployment' interface to represent the folder where wkhtmltox.dll resides. These are the officially supported implementations:

  • EmbeddedDeployment - this is an abstract class with two official implementations: the Win32EmbeddedDeployment and Win64EmbeddedDeployment classes, available from NuGet in their own packages. It contains the wkhtmltopdf file(s) and requires another IDeployment instance to tell it where to create the file(s). This is the recommended and easiest deployment to get started with.
  • TempFolderDeployment - this one generates a temp folder based on the base directory of your application, as well as whether you are running in 32 or 64 bit. Recommended for use with any of the EmbeddedDeployment implementations.
  • StaticDeployment - use this one if you really know what you are doing with TuesPechkin and wkhtmltox.dll. It accepts a string path that you define.

2. Choose a toolset

TuesPechkin exposes an IToolset interface to represent a set of functions from the wkhtmltopdf library. There are three officially supported implementations:

  • PdfToolset - Exposes operations from wkhtmltox.dll to convert HTML into PDF
  • ImageToolset - Exposes operations from wkhtmltox.dll to convert HTML into images
  • RemotingToolset<TToolset> - Manages a toolset of type TToolset across an AppDomain boundary. This is necessary for use in IIS-hosted applications.

There is also an abstract class from which you may inherit: NestingToolset. It provides wrapping functionality that is used by RemotingToolset<TToolset>.

3. Choose a converter

TuesPechkin exposes an IConverter interface. An implementation of IConverter properly makes all of the calls to wkhtmltopdf to convert an IDocument instance (which we will cover shortly.) TuesPechkin supplies two implementations:

  • StandardConverter - A converter that may be used in single-threaded applications
  • ThreadSafeConverter - A converter that manages a single background thread and queues document conversions against it. This is necessary for use in multi-threaded applications, including IIS-hosted applications.

4. Define your document

TuesPechkin exposes three interfaces and one attribute that define an HTML document. These are:

  • WkhtmltoxSettingAttribute: an attribute for properties that instructs an IConverter to apply the property's value to the wkhtmltopdf global or object setting with the name passed to the attribute's constructor.
  • ISettings: a token interface whose implementors are implied to have properties decorated with WkhtmltoxSettingAttribute and/or other ISettings properties.
  • IObject: an interface that represents a wkhtmltopdf 'ObjectSettings'. It requires one method to be implemented: byte[] GetData(). All IObject instances are also ISettings instances by inheritance.
  • IDocument: an interface that represents an HTML document. It requires one method to be implemented: IEnumerable<IObject> GetObjects(). All IDocument instances are also ISettings instances by inheritance.

Because TuesPechkin exposes these interfaces/attributes, you are free to write your own implementations that support whichever wkhtmltopdf settings you so desire. If TuesPechkin's included HtmlDocument class and its related classes do not provide support for a setting you want to use, you may then extend them or create your own classes altogether -- this also goes for use cases where you are only setting a handful of properties and you find the included implementations to be too verbose.

The included HtmlToPdfDocument class and its related classes do not supply any default values to wkhtmltopdf.

Here is how an IDocument is to be processed by an IConverter:

  1. A wkhtmltopdf 'GlobalSettings' is created for the document.
  2. The IDocument is recursively crawled for all ISettings and WkhtmltoxSettingAttribute-decorated properties; these properties are applied to the 'GlobalSettings'.
  3. 'GetObjects()' is called on 'IDocument', and for each 'IObject' that is not null, a wkhtmltopdf 'ObjectSettings' is created and that 'IObject' is recursively crawled for all ISettings and WkhtmltoxSettingAttribute-decorated properties; these properties are applied to the 'ObjectSettings'. The 'ObjectSettings' is then added to the converter.

5. Putting it all together

Create a document with options of your choosing.

var document = new HtmlToPdfDocument
{
    GlobalSettings =
    {
        ProduceOutline = true,
        DocumentTitle = "Pretty Websites",
        PaperSize = PaperKind.A4, // Implicit conversion to PechkinPaperSize
        Margins =
        {
            All = 1.375,
            Unit = Unit.Centimeters
        }
    },
    Objects = {
        new ObjectSettings { HtmlText = "<h1>Pretty Websites</h1><p>This might take a bit to convert!</p>" },
        new ObjectSettings { PageUrl = "www.google.com" },
        new ObjectSettings { PageUrl = "www.microsoft.com" },
        new ObjectSettings { PageUrl = "www.github.com" }
    }
};

Convert it in a quick and dirty console application...

IConverter converter =
    new StandardConverter(
        new PdfToolset(
            new Win32EmbeddedDeployment(
                new TempFolderDeployment())));

byte[] result = converter.Convert(document);

...or in a multi-threaded application...

IConverter converter =
    new ThreadSafeConverter(
        new PdfToolset(
            new Win32EmbeddedDeployment(
                new TempFolderDeployment())));

// Keep the converter somewhere static, or as a singleton instance!
// Do NOT run the above code more than once in the application lifecycle!

byte[] result = converter.Convert(document);

...or in an IIS-hosted application.

IConverter converter =
    new ThreadSafeConverter(
        new RemotingToolset<PdfToolset>(
            new Win32EmbeddedDeployment(
                new TempFolderDeployment())));

// Keep the converter somewhere static, or as a singleton instance!
// Do NOT run the above code more than once in the application lifecycle!

byte[] result = converter.Convert(document);

Use the embedded library from the TuesPechkin.Wkhtmltox.Win64 NuGet package instead.

IConverter converter =
    new StandardConverter(
        new PdfToolset(
            new Win64EmbeddedDeployment(
                new TempFolderDeployment())));

byte[] result = converter.Convert(document);

License

This work, "TuesPechkin", is a derivative of "Pechkin" by gmanny (Slava Kolobaev) used under the Creative Commons Attribution 3.0 license. This work is made available under the terms of the Creative Commons Attribution 3.0 license (viewable at http://creativecommons.org/licenses/by/3.0/) by tuespetre (Derek Gray.)