Fix BUILD-1144: Prevent Neynar API 20-character limit error

[scottrepreneur]

Summary

Fixes BUILD-1144 where Ethereum addresses (42 characters) caused 400 Bad Request errors when searching users via the Neynar API, which has a requirement that the q parameter must be 20 characters or less.

Changes

• Input Validation: Added pre-API validation in searchUsersByUsername() to check string length
• Ethereum Address Detection: Special handling for 42-char strings starting with 0x
• Error Handling: Updated /search route to return proper 400 responses with descriptive messages
• Test Coverage: Added comprehensive tests for validation edge cases

Root Cause

The Neynar /v2/farcaster/user/search endpoint validates that the q parameter is ≤20 characters. When users attempted to search with Ethereum addresses like 0x0B5f5a722Ac5E8EcEDf4da39A656fe5f1e76b34C, the API returned:

{"code":"InvalidField","message":"q must be a string of length 20 or less","property":"q"}

Solution

• Input validation before making API calls prevents 400 errors
• Clear user feedback about search limitations
• Maintains backward compatibility for valid searches

Test Plan

• Added unit tests for Ethereum address search validation
• Added unit tests for long query validation
• Added unit tests for 20-character limit boundary
• Verified existing search functionality still works
• All new tests passing

🤖 Generated with Claude Code

[linear]

BUILD-1144 Neynar has a lookup by name requirement of 20 characters

# Appears to be an issue with the address input here. Not sure who is attempting with address



<-- POST /api/v1/users/search
[DEBUG] 🔍 DEBUG: Starting user search for username: "0x0B5f5a722Ac5E8EcEDf4da39A656fe5f1e76b34C"
[DEBUG] 🔍 DEBUG: Cleaned username: "0x0B5f5a722Ac5E8EcEDf4da39A656fe5f1e76b34C"
[DEBUG] 🔍 DEBUG: Neynar API key configured, making search request for: "0x0B5f5a722Ac5E8EcEDf4da39A656fe5f1e76b34C"
[DEBUG] 🔍 DEBUG: API URL: https://api.neynar.com/v2/farcaster/user/search?q=0x0B5f5a722Ac5E8EcEDf4da39A656fe5f1e76b34C
[DEBUG] 🔍 DEBUG: Neynar API response status: 400 Bad Request
[ERROR] ❌ DEBUG: Neynar API error: 400 Bad Request {"code":"InvalidField","message":"q must be a string of length 20 or less","property":"q"}
[ERROR] ❌ DEBUG: Error during user search: 88658 |             users: []
88659 |           };
88660 |         }
88661 |         const errorText = await response.text();
88662 |         logger3.error(`\u274C DEBUG: Neynar API error: ${response.status} ${response.statusText}`, errorText);
88663 |         throw new Error(`Neynar API error: ${response.status} ${response.statusText}`);
                               ^
error: Neynar API error: 400 Bad Request
      at searchUsersByUsername (/app/dist/index.js:88663:24)
 
--> POST /api/v1/users/search 500 19ms