Fix: image download fails — API returns HTTP URLs but OSS CDN requires HTTPS

[nguyenngothuong]

Problem

The mmx image generate command fails with Network request failed when trying to download generated images.

Root Cause

The MiniMax Image Generation API returns image URLs using HTTP (e.g. http://hailuo-image-*.oss-us-east-1.aliyuncs.com/...), but the Alibaba Cloud OSS US East CDN blocks HTTP traffic from many regions, causing fetch() to fail with Network request failed.

Direct test:

❌ http://hailuo-image-*.oss-us-east-1.aliyuncs.com/... → "fetch failed"
✅ https://hailuo-image-*.oss-us-east-1.aliyuncs.com/... → 200 OK, image downloaded

This affects any region where the OSS CDN blocks HTTP traffic (confirmed from Vietnam, likely affects other regions too).

Solution

Fix 1: Force HTTPS in download.ts

Auto-convert http:// → https:// before fetching:

const downloadUrl = url.startsWith('http://') ? url.replace('http://', 'https://') : url;

Fix 2: Add --response-format base64 option

The API supports response_format: base64 which returns base64-encoded images directly, completely bypassing the CDN download step. This is useful as a fallback when CDN URLs are unreachable.

Files Changed

File	Change
src/files/download.ts	Force HTTPS + retry logic (3 attempts, exponential backoff)
src/commands/image/generate.ts	Add `--response-format <url
src/types/api.ts	Add response_format to ImageRequest, image_base64 to ImageResponse

Test Results

# Default (HTTP→HTTPS fix)
mmx image "A sunset over mountains" --out-dir ./out/
# ✅ Saved: ./out/image_001.jpg (290KB, 1024x1024 JPEG)

# Base64 mode (bypasses CDN entirely)
mmx image "A cat wearing sunglasses" --response-format base64 --out-dir ./out/
# ✅ Saved: ./out/image_001.jpg (571KB, 1024x1024 JPEG)

Both modes produce valid JPEG images successfully.

Note

This is an infrastructure-side issue (OSS CDN blocking HTTP) that the CLI can work around on the client side. The ideal long-term fix would be for MiniMax to return HTTPS URLs directly from the API.