Collect new RSS articles into Google Sheets without duplicates

flowchart TD trig(["scheduled check of RSS feeds"]):::trigtime s0["validate feed urls"]:::task s1[["fetch latest articles"]]:::mi s2["collect article details"]:::task s3["write article as new row"]:::task trig --> s0 s0 -->|"one per one per RSS feed"| s1 s1 --> s2 s2 --> s3 out[/"sheet updated with new articles"/]:::out pay{{"centralized deduplicated content log"}}:::pay s3 --> out out --> pay classDef task fill:#e7f6fe,stroke:#34b8f0,color:#2c2a29 classDef svc fill:#f6f8fa,stroke:#7c8795,color:#2c2a29 classDef mi fill:#e7f6fe,stroke:#0079a8,color:#2c2a29,stroke-width:2px classDef human fill:#fff,stroke:#0079a8,color:#0079a8 classDef store fill:#f6f8fa,stroke:#0079a8,color:#2c2a29 classDef trig fill:#00a4eb,stroke:#0079a8,color:#fff,font-weight:bold classDef trigtime fill:#00a4eb,stroke:#0079a8,color:#fff,font-weight:bold classDef trigdata fill:#8ad4f5,stroke:#0079a8,color:#06314c,font-weight:bold classDef gate fill:#fff,stroke:#e8a23d,color:#6b4708,font-weight:bold classDef out fill:#1f9d6b,stroke:#167a53,color:#fff,font-weight:bold classDef pay fill:#06314c,stroke:#021f33,color:#fff