Debugging

S3 Browser Direct Upload CORS Pitfall Record: Complete Debugging Process from "Network Error" to Dual-Cloud Upload

Based on practical experience with the JoyMini dual-cloud storage architecture, this article fully documents the debugging process from "Featured image upload failed: network error" to identifying the missing CORS configuration on the S3 bucket, including analysis of the browser preflight mechanism, CLI instant fix, CDK persistent configuration, and key differences in CORS behavior between R2 and S3.