Hi Thommees,

I can't answer this all in one go: but I will start off the post with what I have so far: and I'll continue to post updates to this as I go along.

I'm using PRPC72 here - but this should pretty much apply to any 7.x version .....(and probably lower).

Cheers

John

PART ONE : How do you Create a ZIP file in Java ?

Since PRPC is built on Java; I find it sometimes helpful to build a simple standalone Java Program to give me something to aim for - its useful also to see what imports are needed an the like.

Here's a basic working example of creating a ZIP file with some dummy content (they are real files; but they all just contain 'hello world'):

// See: https://stackoverflow.com/questions/1091788/how-to-create-a-zip-file-in-java
package com.pega.gcs.zipit;

import java.io.FileOutputStream;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;

public class ZipIt {
    String zipOutputName="test.zip";
    String[] filesInZip={ "one.txt", "b/two.txt", "a/b/three.txt" };
   
    public ZipIt() {
       
    }
   
    public void WriteZip() {
        try {
            String DummyContent="Hello World.";
            byte[] data=DummyContent.getBytes("UTF8");
            FileOutputStream fout=new FileOutputStream(this.zipOutputName);
            ZipOutputStream zout = new ZipOutputStream(fout);
            for (String zipEntryName : this.filesInZip ) {
                ZipEntry ze=new ZipEntry( zipEntryName );
                zout.putNextEntry(ze);
                zout.write(data, 0, data.length);
                zout.closeEntry();
            }
            zout.close();
        }
        catch(Exception e) { throw new RuntimeException(e); }
    }
   
    public static void main(String[] args) {
        ZipIt zipit=new ZipIt();
        zipit.WriteZip();
       
    }  
}

I'll attach this for reference here; along with a Maven 'POM' file (although everything is using Java Libraries, so it's not strictly necessary here).

I'll also attach the simple 'test.zip' it creates to show it works.

PART TWO: How does PRPC store Work Item Attachments ?

I have just created a simple Test Application in PRPC - I logged into the 'User Portal' and created a Work Item : it was assigned the Work Item of 'T-4' and attached three files, a PNG, a PDF and a TEXT File - like this:

So where are these stored ? I checked the PRPC Help, this page is useful for our purposes:

http://host:port/prhelp/procomhelpmain.htm#concepts/casemanagement/con_conceptsattachments.htm

Extract:

Classes for attachments

The system stores attachments in instances of the following concrete classes, subclasses of the Data-Work Attach- class:

    Data-WorkAttach-File — Holds files of any type and format, including PDF files generated by an application.

    Data-WorkAttach-Note — Contains text that is pasted into, or typed directly into, a work item.

    Data-WorkAttach-URL — Records an Internet Uniform Resource Locator (URL) or Uniform Resource Identifier (URI).

    Data-WorkAttach-ScreenShot — Holds screen shot attachments that usually record facts about the work item that were obtained from another system.

    Data-WorkAttach-ScanDocument — Contains a TIFF image file created by a scanner.

    Data-WorkAttach-ECM — File attachments saved in an external enterprise content management (ECM) system, accessed through a Connect CMIS rule.

By default, attachments are stored as rows of the pc_data_workattach table. Attachments are not stored in the same database table as the cases.

So: in fact there are different types of attachments ; so for a first draft of this - I'll stick to the simple 'Data-WorkAttach-File' types for now.

In my Designer Studio - I added the class 'Data-WorkAttach-File' to my 'pinned-classes' (we're going to look here frequently probably...); and double-clcking on this pinned-class - this brings up the instances; we can see the 3 attachments that are associated with the Work Item 'T-4': (I restricted my search to include my Work Class only, which is called 'Zip-Zipit-Work').

Its also useful to check the definition of the Class itself - to see what the 'keys' are :

So the keys are 'pxRefObjectKey' and 'pxAttachKey'; lets now look at an example instance and see what those keys are in that case; on the previous 'instances' screen - I just clicked on an instance

Tip #1: Since we are dealing with large amounts of data here (attachments) - I picked the 'hello.txt' file, because I know that is small, rather than PDF for instance!

Tip #2: Make sure your Pop-Up Blocker isn't stopping you opening up a new window !

Here's a screenshot showing the Instance Data of the 'hello.txt' attachment to Work Item 'T-4':

So here's a snippet of that XML above:

<pagedata>
    <pxInsName>ZIP-ZIPIT-WORK T-4!20160422T144234.228 GMT</pxInsName>
    <pxAttachKey>20160422T144234.228 GMT</pxAttachKey>
    <pzDocumentKey>DATA-WORKATTACH-FILE ZIP-ZIPIT-WORK T-4!20160422T144234.228 GMT</pzDocumentKey>
    <pyRuleHarness>RuleFormLegacy</pyRuleHarness>
    <pxLimitedAccess>Dev</pxLimitedAccess>
    <pyNote>hello</pyNote>
    <pxRefObjectClass>Zip-ZipIt-Work-Ticket</pxRefObjectClass>
    <pyRuleFormStatusTime>20160422T145323.444 GMT</pyRuleFormStatusTime>
    <pxAttachName>hello.txt</pxAttachName>
    <pxRefObjectKey>ZIP-ZIPIT-WORK T-4</pxRefObjectKey>
    <pyRuleFormType>Form</pyRuleFormType>
    <pxCreateDateTime>20160422T144234.226 GMT</pxCreateDateTime>
    <pyShowJavaWindowName>GeneratedJava20160422T145323.449 GMT</pyShowJavaWindowName>
    <pxCreateOpName>Administrator</pxCreateOpName>
    <pxSaveDateTime>20160422T144234.229 GMT</pxSaveDateTime>
    <pxApplication>ZipIt</pxApplication>
    <pxTabLabel>ZIP-ZIPIT-WORK T-4!20160422T144234.228 GMT</pxTabLabel>
    <pxCommitDateTime>20160422T144234.000 GMT</pxCommitDateTime>
    <pyRuleFormStatus>Good</pyRuleFormStatus>
    <pxAttachedByWorkgroup>default@zip</pxAttachedByWorkgroup>
    <pxAttachedByOrganization>zip</pxAttachedByOrganization>
    <pxAttachedByOrgUnit>Unit</pxAttachedByOrgUnit>
    <pzInsKey>DATA-WORKATTACH-FILE ZIP-ZIPIT-WORK T-4!20160422T144234.228 GMT</pzInsKey>
    <!-- [...] -->
    <pxAttachedBy>Admin@zip</pxAttachedBy>
    <pyCategory>File</pyCategory>
    <pzSkipCreateCMISDocument>true</pzSkipCreateCMISDocument>
    <pxAttachedByOrgDivision>Div</pxAttachedByOrgDivision>
    <pyAttachStream>SGVsbG8gV29ybGQgIQ==</pyAttachStream>
</pagedata>

So we can see that the Work Item reference is held as :

<pxRefObjectKey>ZIP-ZIPIT-WORK T-4</pxRefObjectKey>

And the rest of the KEY appears to be based on a DateTime value:

<pxAttachKey>20160422T144234.228 GMT</pxAttachKey>

And the content appears to be held as (base64 encoded) this:

<pyAttachStream>SGVsbG8gV29ybGQgIQ==</pyAttachStream>

PART THREE: How do we access the Attachment Data programmatically ?

Lets try an 'OBJ-BROWSE' in PRPC to fetch the attachment data from our single test Work Item ('T-4').

This Activity does this (I have rather optmisitically named this Activity as 'ZipUpAttachments' - but it doesn't do anything of the sort yet ;-) )

I have set MaxRecords to 10 ; just as a 'safety-valve'  -since we don't want to 'running away' at this point - as Attachment Data may be very large of course.

And at this point: we are NOT fetching the content - just the name of the attachment to confirm we are getting back what we want.

Running this:

Results in this page of 'pxResults' being built for us :it contains the Three Attachments we seek.... (hurrah!)

And here's the XML snippet of this pxResults Page: (which is actually embedded in another page, which contains other meta-data etc) :

<pxResults REPEATINGTYPE="PageList">
    <rowdata REPEATINGINDEX="1">
        <pxAttachName>face.png</pxAttachName>
        <pxRefObjectKey>ZIP-ZIPIT-WORK T-4</pxRefObjectKey>
        <pxObjClass>Data-WorkAttach-File</pxObjClass>
    </rowdata>
    <rowdata REPEATINGINDEX="2">
        <pxAttachName>pega-72-platform-upgrade-guide.pdf</pxAttachName>
        <pxRefObjectKey>ZIP-ZIPIT-WORK T-4</pxRefObjectKey>
        <pxObjClass>Data-WorkAttach-File</pxObjClass>
    </rowdata>
    <rowdata REPEATINGINDEX="3">
        <pxAttachName>hello.txt</pxAttachName>
        <pxRefObjectKey>ZIP-ZIPIT-WORK T-4</pxRefObjectKey>
        <pxObjClass>Data-WorkAttach-File</pxObjClass>
    </rowdata>
</pxResults>

So far , so good - we can identify the attachments for a particular Work Item.

This is as far as I have got at time point; but I would suggest the next things to work out would be:

1. How to get at the Content ? We'll need to convert B64 encoded content to an array of Bytes...

2. How to Generate a ZIP file and write each file of the raw Bytes into a Zip Entry: where are we going to store this ZIP file ? In-memory ? A temporary file ? Are we going to create a Folder Structure or just a 'flat' structure....

3. Then we need to try the last bit of your question: how to re-attach the resultant ZIP.

I'll be back......