```yaml product: AlterLab title: Aligning Protected Storage Capture and Restore Contracts in AlterLab category: Product Updates comparison_context: "AlterLab is an alternative to Firecrawl, ScrapingBee, and Bright Data." last_updated: 2026-09-25 canonical_facts: - "Learn how AlterLab repaired its protected-storage producer/consumer contract to enable safe promotion from staging to main while preserving database snapshots, redaction, financial, and usage guarantees." source_url: https://alterlab.io/blog/aligning-protected-storage-capture-and-restore-contracts-in-alterlab ``` ## TL;DR AlterLab repaired the protected-storage producer/consumer contract that was blocking promotion from staging to main. The fix aligns capture and restore semantics, preserves database snapshots, redaction, financial, and usage contracts, and classifies mixed-volume paths by meaning rather than file extension. ## The Problem: A Broken Producer/Consumer Contract AlterLab’s protected storage layer stores scrape results, snapshots, and metadata. Two sides interact with it: - **Producer** – the capture process that writes new data after a scrape. - **Consumer** – the restore process that reads data for retries, audits, or downstream pipelines. A contract between these sides guarantees: 1. Database snapshots remain consistent. 2. Redaction rules are applied uniformly. 3. Financial and usage metering stays accurate. 4. Object‑class requirements (e.g., encryption, retention) are honored. During a recent staging→main promotion, the contract failed because capture and restore were classifying storage objects differently. Capture used MIME‑type detection; restore relied on file extensions. This mismatch meant a restored object could inherit the wrong encryption class or retention policy, violating snapshot and financial guarantees. ## Solution: Align Capture and Restore Semantics The fix involved three steps: 1. **Unified Classification Logic** – Both producer and consumer now run the same semantic‑path classifier. Instead of checking `.json` or `.html`, the system examines the *meaning* of the path (e.g., “scrape‑result”, “snapshot”, “redacted‑log”) and applies the appropriate object class. 2. **Contract‑Preserving Transforms** – All transforms (redaction, compression, encryption) are expressed as pure functions of the classified object class. This ensures that applying a transform during capture yields an identical result when the same transform is applied during restore. 3. **Metadata Versioning** – A version field was added to stored objects. If a consumer encounters an older version, it can safely upgrade or downgrade using a documented migration path without breaking snapshots or usage contracts. The result is a bidirectional contract: any object written by the producer can be read by the consumer with guaranteed fidelity, and vice‑versa. ## Classifying Mixed‑Volume Semantic Paths, Not Extensions AlterLab’s storage spans multiple volumes (hot SSD, warm NAS, cold archive). Previously, routing decisions were based on file extension, causing: - Mis‑routed snapshots (e.g., a `.json` snapshot sent to cold storage despite needing fast restore). - Inconsistent redaction (a redacted log mistakenly treated as raw data). - Usage‑meter drift (objects counted against the wrong volume tier). The new classifier examines: - **Path prefix** (`/scrape-result/`, `/snapshot/`, `/audit/`) - **User‑defined tags** (e.g., `pii:true`, `retention:30d`) - **Content hints** (first‑kilobyte analysis for structured vs binary data) Based on these signals, the system assigns an object class that determines: - Target volume (hot/warm/cold) - Encryption profile - Retention policy - Usage‑meter label This semantic approach eliminates extension‑based edge cases and makes the producer/consumer contract deterministic across all volumes. ## Code Example: Capturing a Scrape Result with Protected Storage Below is a Python snippet showing how a capture job stores a scrape result using the updated contract. The example uses AlterLab’s Python SDK and demonstrates setting semantic tags that drive classification. ```python title="capture_scrape.py" {3-8} import alterlab from alterlab.storage import StorageObject, ObjectClass # Initialize client (alterlab.io web-scraping-api-python) client = alterlab.Client("YOUR_API_KEY") # highlighted # Perform a scrape (any target URL) scrape_resp = client.scrape( url="https://example.com/products", params={"render": True, "format": "json"} ) # highlighted # Build a storage object with semantic tags obj = StorageObject( bucket="scrape-results", key=f"scrape-result/{scrape_resp.id}", body=scrape_resp.text, tags={ "type": "scrape-result", "source": "e-commerce", # generic category, not a specific site "pii": "false" }, obj_class=ObjectClass.from_tags({"type": "scrape-result", "pii": "false"}) ) # highlighted # Store via protected storage API (internal contract) client.storage.put(obj) # highlighted ``` **What this does:** - The scrape result is tagged as `type:scrape-result`. - The `StorageObject` constructor derives the correct `ObjectClass` from those tags. - `client.storage.put` routes the object to the appropriate volume, applies encryption, and updates usage meters—all guaranteed by the restored producer/consumer contract. ## Code Example: Restoring a Scrape Result via cURL The following cURL command shows how a consumer (e.g., a retry worker) retrieves the same object, relying on the aligned contract to receive identical metadata and content. ```bash title="Terminal" {3-7} curl -X POST https://api.alterlab.io/v1/storage/get \ -H "X-API-Key: YOUR_KEY" \ -d '{ "bucket": "scrape-results", "key": "scrape-result/12345-abcd", "tags": { "type": "scrape-result", "source": "e-commerce", "pii": "false" } }' # highlighted ``` **Key points:** - The request repeats the semantic tags used during capture. - The storage service consults the shared classifier, selects the same object class, and returns the object with its original encryption and retention settings. - Because the contract is symmetric, the consumer can trust that the restored byte stream matches what the producer originally wrote. ## Infographic: Capture → Store → Restore Flow