PassKit

This is a library for generating Apple Wallet PKPasses.

How to use

This library was heavily inspired by drallgood's jpasskit library which was written in Java, so the objects and functions are very similar to the ones available on jpasskit.

Define a pass

To define a pass you use the Pass struct, which represents the pass.json file. This struct is modeled as closely as possible to the json file, so adding data is straightforward:

c := passkit.NewBoardingPass(passkit.TransitTypeAir)
field := passkit.Field{
    Key: "key",
    Label: "label",
    Value:"value",
}

c.AddHeaderField(field)
c.AddPrimaryFields(field)
c.AddSecondaryFields(field)

p := passkit.Pass{
    FormatVersion:       1,
    TeamIdentifier:      "TEAMID",
    PassTypeIdentifier:  "pass.type.id",
    AuthenticationToken: "123141lkjdasj12314",
    OrganizationName:    "Your Organization",
    SerialNumber:        "1234",
    Description:         "test",
    BoardingPass:         c,
    Barcodes: []passkit.Barcode{
        {
            Format:          passkit.BarcodeFormatPDF417,
            Message:         "1312312312312312312312312312",
            MessageEncoding: "utf-8",
        },
    },
}

Templates

Usually, passes contain additional information that need to be included in the final, signed pass, e.g.

Images (icons, logos, background images)
Translations

These templates are defined in the apple wallet developer documentation.

To create the pass structure you need a PassTemplate instance, either using streams (with InMemoryPassTemplate) or files (with FolderPassTemplate).

Using files

To load the pass with files in the file system you create an instance of FolderPassTemplate passing the absolute file path of the folder:

folderTemplate := passkit.NewFolderPassTemplate("/home/user/pass")

When building the pass the files in the folder will be added.

Using streams (In Memory)

The second approach is more flexible, having the option of loading files using data streams:

memTemplate := passkit.NewInMemoryPassTemplate()

memTemplate.AddFileBytes(passkit.BundleThumbnail, bytes)
memTemplate.AddFileBytesLocalized(passkit.BundleIcon, "en", bytes)
err := memTemplate.AddFileFromURL(passkit.BundleLogo, "http://example.com/file.png")
err := memTemplate.AddFileFromURLLocalized(passkit.BundleLogo, "en", "http://example.com/file.png")
err := memTemplate.AddAllFiles("/home/user/pass")

Note: There are no checks, that the content of a provided file is valid. So if you'd provide a PDF file but store it as icon.png, it will not work.

Signing and zipping a pass

To create a pkpass file you need to use a Signer. There are two types of signers:

FileBasedSigner (uses a temp folder to create the zip file)
MemoryBasedSigner (creates the zip on memory as bytes)

To use any of the Signer instances you need an instance of SigningInformation. There are two methods to obtain an instance:

signer, err := passkit.LoadSigningInformationFromFiles("/home/user/pass_cert.p12", "password", "/home/user/AppleWWDRCA.cer")
signer, err := passkit.LoadSigningInformationFromBytes(passCertBytes, "password", wwdrcaBytes)

To create a zip you use the Pass, Signer, SigningInformation, and PassTemplate instances created previously:

signer := passkit.NewMemoryBasedSigner()
z, err := signer.CreateSignedAndZippedPassArchive(&pass, template, signInfo)
if err != nil {
    panic(err)
}

err = ioutil.WriteFile("/home/user/pass.pkpass", z, 0644)
if err != nil {
    panic(err)
}