fix(http): serialize nested objects in form-urlencoded body

[waleedlatif1]

Summary

• Fix URLSearchParams corrupting nested objects/arrays to [object Object]
• JSON.stringify object values in form-urlencoded body serialization

Fixes#3109

Type of Change

• Bug fix

Testing

Tested manually

Checklist

• Code follows project style guidelines
• Self-reviewed my changes
• Tests added/updated and passing
• No new warnings introduced
• I confirm that I have read and agree to the terms outlined in the Contributor License Agreement (CLA)

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1 Skipped Deployment

Project	Deployment	Actions	Updated (UTC)
docs	Skipped		Feb 3, 2026 6:23pm

[greptile-apps]

Greptile Overview

Greptile Summary

Fixed URLSearchParams corruption when serializing nested objects/arrays in application/x-www-form-urlencoded request bodies. Previously, objects were converted to [object Object] string. Now uses JSON.stringify for object values while preserving primitive serialization with String().

Changes:

• Modified request.ts:108-111 to conditionally apply JSON.stringify for object-type values
• Added test case verifying nested objects serialize to URL-encoded JSON strings (e.g., data=%7B%22nested%22%3A%22value%22%7D)
• Test confirms arrays are handled correctly (items=%5B1%2C2%2C3%5D)

The fix addresses issue #3109 and includes test coverage that was requested in previous review feedback.

Confidence Score: 4/5

• Safe to merge with minor consideration for edge cases
• The implementation correctly fixes the nested object serialization bug and includes proper test coverage. However, there's a potential edge case with circular references in JSON.stringify that could throw errors in rare scenarios. The fix is well-targeted and doesn't introduce breaking changes to existing functionality.
• No critical files require special attention, though request.ts could benefit from error handling for edge cases

Important Files Changed

Filename	Overview
apps/sim/tools/http/request.ts	Fixed nested object serialization in form-urlencoded bodies using JSON.stringify, preventing [object Object] corruption
apps/sim/tools/http/request.test.ts	Added comprehensive test coverage for nested objects and arrays in form-urlencoded serialization

Sequence Diagram

sequenceDiagram
participant Client
participant requestTool
participant URLSearchParams
participant fetch
Client->>requestTool: POST with nested body & form-urlencoded header
Note over Client,requestTool: body: {name: 'test', data: {nested: 'value'}, items: [1,2,3]}
requestTool->>requestTool: Check Content-Type header
alt Content-Type is application/x-www-form-urlencoded
requestTool->>URLSearchParams: new URLSearchParams()
loop For each key-value pair
alt value is object
requestTool->>requestTool: JSON.stringify(value)
Note over requestTool: {nested: 'value'} → '{"nested":"value"}'<br/>[1,2,3] → '[1,2,3]'
else value is primitive
requestTool->>requestTool: String(value)
Note over requestTool: 'test' → 'test'
end
requestTool->>URLSearchParams: append(key, stringified_value)
end
URLSearchParams->>requestTool: URL-encoded string
Note over URLSearchParams: 'name=test&data=%7B%22nested%22%3A%22value%22%7D&items=%5B1%2C2%2C3%5D'
end
requestTool->>fetch: HTTP request with serialized body
fetch-->>requestTool: Response
requestTool-->>Client: Result

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[greptile-apps]

_{1 file reviewed, 2 comments}

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[waleedlatif1]

@greptile

[waleedlatif1]

@greptile

[greptile-apps]

_{2 files reviewed, 1 comment}

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