Wednesday, January 20, 2010

Base64 Encoding Binary Files

Several months ago I posted a handful of methods for base64 encoding strings. At that time I suggested that the next important step was base64 encoding binary files. This represents a challenge because PeopleCode does not offer methods for reading binary files. The following PeopleCode uses the Java API and the Apache Commons Codec library to show how to base64 encode a binary file. To run this example, download the commons-codec library and place the jar file in your local %PS_HOME\class directory. Next, create an App Engine with a PeopleCode step and insert the following PeopleCode:

Local JavaObject &f_in = CreateJavaObject("", "c:\temp\binaryfile.gif");
Local JavaObject &coder_in = CreateJavaObject("org.apache.commons.codec.binary.Base64InputStream", &f_in, True);
Local JavaObject &reader = CreateJavaObject("", CreateJavaObject("", &coder_in));

Local string &b64Data = "";
Local any &line;

While True
&line = &reader.readLine();
If (&line <> Null) Then
&b64Data = &b64Data | &line | Char(13) | Char(10);


Local File &b64File = GetFile("c:\temp\base64_encoded.txt", "A", "A", %FilePath_Absolute);

The Java objects at the top of this listing read binary data from a file and transform that data into a base64 text listing, which is then stored in the variable &b64Data. For demonstration purposes, I wrote the contents of &b64Data to a file. In real life, you would add this contents to a CDATA node prior to sending a message through the Integration Broker.

Before running this code, replace c:\temp\binaryfile.gif with the full path to a real binary file on your workstation. After adding the PeopleCode listed above, disable restart and run your App Engine. When the App Engine completes, look in your local c:\temp directory for a file named base64_encoded.txt.