Add $flow to Variable Resolution in Flow Building Process

[raffareis]

Changes Overview

This PR enhances the variable resolution process in the flow building mechanism, particularly focusing on the buildFlow and getVariableValue functions.

Key Updates

1. Flow Options Enhancement

   • Added a new options object in the buildFlow function:

     const options: ICommonObject = {
         chatflowid,
         chatId,
         sessionId,
         chatHistory
     }

2. Variable Resolution Improvements

   • Updated resolveVariables and getVariableValue functions to accept and utilize the new options parameter.

3. Flow-specific Variable Support

   • Implemented handling for variables starting with $flow. in the getVariableValue function:

     if (variableFullPath.startsWith('$flow.') && options) {
         const variableValue = get(options, variableFullPath.replace('$flow.', ''))
         if (variableValue) {
             variableDict[`{{${variableFullPath}}}`] = variableValue
             returnVal = returnVal.split(`{{${variableFullPath}}}`).join(variableValue)
         }
     }

Rationale

These changes allow for more flexible and context-aware variable resolution within the flow building process. By introducing the options object and supporting $flow. prefixed variables, we enable access to flow-specific data like chatflowid, chatId, sessionId, and chatHistory during variable resolution.

Also it can be used to enhance filtering and logic in any flow input:

Testing

Notes for Reviewers

• Pay special attention to the variable resolution logic in getVariableValue.
• Consider if there are any edge cases in flow-specific variable usage that should be addressed.

[HenryHengZJ]

@raffareis I tried something like this:

but somehow the $flow is not getting replaced with value:

[raffareis]

@HenryHengZJ nice catch. Here we go.
bbf8cee

[raffareis]

Also did a little refactor. Instead of an additional parameter, I merged overrideConfig and options into flowData. Bonus that it will work for agent flows as well because of that.

d3662bc

[HenryHengZJ]

thanks @raffareis !