HTTP requests fail with 308 redirects from Safe Transaction Service API #25

Description

When using the Safe library to propose transactions via the Safe Transaction Service API, requests fail with a ProposeTransactionFailed(308, ...) error containing an HTML redirect page.

Root Cause

The underlying solidity-http library uses curl without the -L flag, so HTTP redirects are not followed. The Safe Transaction Service API returns 308 Permanent Redirect responses (likely for URL normalization), which causes the request to fail.

Error Output

ProposeTransactionFailed(308, "\r308 Permanent Redirect\r\r308 Permanent Redirect\rnginx\r\r")

Fix

A fix has been submitted to the solidity-http library:
Recon-Fuzz/solidity-http#1

Once merged, updating the solidity-http dependency will resolve this issue.

Workaround

Manually patch lib/solidity-http/src/HTTP.sol line 150 to add redirect support by adding the -L flag:

- string memory scriptStart = 'response=$(curl -s -w "\\n%{http_code}" ';
+ string memory scriptStart = 'response=$(curl -sL -w "\\n%{http_code}" ';