fix: Robust barcode scan handling for ANSI MH10.8.2 and InvenTree 1.x

- Capture scanner control keystrokes (Ctrl+]/^/\/_ → GS/RS/FS/US) in the
  scan input so ANSI MH10.8.2 field separators survive the HTML input
  filter, eliminating the Q-quantity-vs-next-DI ambiguity.
- Fall back to a DI-aware lazy regex when separators are stripped
  (e.g. pasted scans), so Q digits stop at the next data identifier
  instead of greedily eating into 11Z/12Z/etc.
- Make pending-part dicts JSON-serializable by isoformat-ing the
  timestamp; without this the worker's import_complete socket emit
  threw and the entry was never removed from the queue, causing
  every re-scan to 400 with "already queued" forever.
- Make /api/part/import idempotent: a re-scan of an already-queued
  part updates qty/location and returns 200 with already_queued=true
  instead of 400.
- Surface search/queue errors in the client log instead of silently
  swallowing them, and stop treating a 500 from /api/part/search as
  "not found" (which was causing re-queue loops).
- Log full tracebacks for /api/part/search failures and split the
  get_part_info / get_part_parameters error paths so failures can be
  attributed.
- Migrate get_part_parameters to the InvenTree 1.x endpoint
  /api/parameter/?model_type=part.part&model_id=<id>. The old
  /api/part/parameter/?part=<id> returns 404 on this instance, and
  even on the new endpoint the ?part= filter is silently ignored
  (would have returned every parameter in the database).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.claude/settings.local.json

@@ -14,7 +14,11 @@
       "Bash(npx svelte-kit *)",
       "Bash(npx svelte-check *)",
       "Bash(npm run *)",
-      "Bash(npx tsx *)"
+      "Bash(npx tsx *)",
+      "Bash(git commit *)",
+      "Bash(git push *)",
+      "WebFetch(domain:inventree-b4l.newedge.house)",
+      "Bash(C:/dev/inventree-stock-tool/.venv/Scripts/python.exe *)"
     ],
     "deny": [],
     "ask": []

src/stocktool/stock_tool_gui_v2.py

@@ -299,9 +299,17 @@ def get_part_parameters(host: str, token: str, part_id: int) -> List[Dict[str, A
     Returns:
         List of parameter dictionaries
     """
-    url = f"{host}/api/part/parameter/"
+    # InvenTree 1.x consolidated parameters under /api/parameter/ keyed by
+    # generic (model_type, model_id). The old /api/part/parameter/?part=<id>
+    # endpoint no longer exists, and just `?part=<id>` on the new endpoint
+    # is silently ignored (returns every parameter in the database).
+    url = f"{host}/api/parameter/"
     headers = {'Authorization': f'Token {token}'}
-    resp = requests.get(url, headers=headers, params={'part': part_id})
+    resp = requests.get(
+        url,
+        headers=headers,
+        params={'model_type': 'part.part', 'model_id': part_id},
+    )
     resp.raise_for_status()
 
     data = resp.json()
@@ -461,12 +469,26 @@ def parse_scan(raw: str) -> Tuple[Optional[str], Optional[int]]:
         part = None
         qty = None
 
-        # Extract part number - it's after [)>06P and before the next field marker
-        # Look for common field markers: 1P, 30P (these are explicit markers)
+        # If GS/RS separators survived, parse field-by-field — unambiguous.
+        fields = SEP_RE.split(raw)
+        if len(fields) > 1:
+            for f in fields:
+                if not f:
+                    continue
+                if f.startswith('30P'):
+                    part = clean_part_code(f[3:])
+                elif f.startswith('1P'):
+                    if not part:
+                        part = clean_part_code(f[2:])
+                elif f.startswith('Q') and f[1:].isdigit():
+                    qty = int(f[1:])
+            if part or qty:
+                return part, qty
+
+        # Separators stripped — extract part after [)>06P up to next field marker.
         if len(raw) > 6 and raw[5] == 'P':
             after_p = raw[6:]
 
-            # Find the next explicit field marker
             markers_to_find = ['1P', '30P']
             end_idx = len(after_p)
 
@@ -477,11 +499,11 @@ def parse_scan(raw: str) -> Tuple[Optional[str], Optional[int]]:
 
             part = clean_part_code(after_p[:end_idx])
 
-        # Extract quantity after Q
-        if 'Q' in raw:
-            q_matches = re.findall(r'Q(\d+)', raw)
-            if q_matches:
-                qty = int(q_matches[0])
+        # Lazy-match Q digits, stopping at the next data identifier
+        # (e.g. 11Z, 12Z, 20Z, 1T, 9D, 4L) or end-of-string.
+        q_match = re.search(r'Q(\d+?)(?=\d{0,2}[A-Z]|$)', raw)
+        if q_match:
+            qty = int(q_match.group(1))
 
         if part or qty:
             return part, qty

src/stocktool/web/app.py

@@ -7,6 +7,7 @@ A Flask-based web interface for barcode scanning and inventory management.
 
 import os
 import sys
+import traceback
 from pathlib import Path
 from flask import Flask, render_template, request, jsonify
 from flask_socketio import SocketIO, emit
@@ -61,6 +62,15 @@ def load_config():
     }
 
 
+def _pending_to_dict(p: PendingPart) -> dict:
+    """JSON-safe serialization of a PendingPart (datetime → isoformat)."""
+    d = asdict(p)
+    ts = d.get('timestamp')
+    if isinstance(ts, datetime):
+        d['timestamp'] = ts.isoformat()
+    return d
+
+
 def on_import_complete(result: ImportResult):
     """Handle import completion callback."""
     pending_part = pending_parts.get(result.part_code)
@@ -73,7 +83,7 @@ def on_import_complete(result: ImportResult):
             'part_code': result.part_code,
             'part_id': result.part_id,
             'success': True,
-            'pending_part': asdict(pending_part)
+            'pending_part': _pending_to_dict(pending_part)
         })
 
         # Remove from pending
@@ -141,9 +151,29 @@ def search_part():
         part_id = find_part(config['host'], config['token'], part_code)
 
         if part_id:
-            # Get part details
-            part_info = get_part_info(config['host'], config['token'], part_id)
-            parameters = get_part_parameters(config['host'], config['token'], part_id)
+            # Get part details — wrap each call so we can pinpoint which one
+            # raised. A 500 here used to be misread by the client as "not
+            # found", which then re-queued the part in an infinite loop.
+            try:
+                part_info = get_part_info(config['host'], config['token'], part_id)
+            except Exception as e:
+                print(f"[search_part] get_part_info({part_id}) failed: {e}")
+                traceback.print_exc()
+                return jsonify({
+                    'success': False,
+                    'stage': 'get_part_info',
+                    'part_id': part_id,
+                    'error': str(e),
+                }), 500
+
+            try:
+                parameters = get_part_parameters(config['host'], config['token'], part_id)
+            except Exception as e:
+                print(f"[search_part] get_part_parameters({part_id}) failed: {e}")
+                traceback.print_exc()
+                # Don't fail the whole search just because parameters errored —
+                # the part exists; surface what we have.
+                parameters = []
 
             return jsonify({
                 'success': True,
@@ -159,6 +189,8 @@ def search_part():
             })
 
     except Exception as e:
+        print(f"[search_part] unexpected failure for {part_code!r}: {e}")
+        traceback.print_exc()
         return jsonify({'success': False, 'error': str(e)}), 500
 
 
@@ -174,9 +206,20 @@ def queue_part_import():
     if not part_code:
         return jsonify({'success': False, 'error': 'part_code required'}), 400
 
-    # Check if already queued
+    # Idempotent: if already queued, acknowledge with the existing entry so
+    # re-scans don't surface as 400s. Update qty/location to the latest scan
+    # values — user likely re-scanned to correct something.
     if part_code in pending_parts:
-        return jsonify({'success': False, 'error': 'Part already queued for import'}), 400
+        existing = pending_parts[part_code]
+        if quantity is not None:
+            existing.quantity = quantity
+        if location_id:
+            existing.location_id = location_id
+        return jsonify({
+            'success': True,
+            'already_queued': True,
+            'pending_part': _pending_to_dict(existing)
+        })
 
     # Create pending part
     pending_part = PendingPart(
@@ -193,7 +236,7 @@ def queue_part_import():
 
     return jsonify({
         'success': True,
-        'pending_part': asdict(pending_part)
+        'pending_part': _pending_to_dict(pending_part)
     })
 
 
@@ -395,7 +438,7 @@ def get_pending():
     """Get all pending part imports."""
     return jsonify({
         'success': True,
-        'pending': [asdict(p) for p in pending_parts.values()]
+        'pending': [_pending_to_dict(p) for p in pending_parts.values()]
     })
 
 

src/stocktool/web/static/js/app.js

@@ -165,6 +165,27 @@ function stockApp() {
             return loc ? `${loc.id} - ${loc.name}` : `Location ${this.currentLocation}`;
         },
 
+        /**
+         * Capture scanner control keystrokes (GS/RS/FS) that <input type="text">
+         * would otherwise drop. HID scanners send field separators as Ctrl+key
+         * combos — without this the ANSI MH10.8.2 separators are lost and the
+         * parser has to guess where Q's digits end.
+         */
+        onScanKeydown(e) {
+            if (!e.ctrlKey || e.altKey || e.metaKey) return;
+
+            let ctrlChar = null;
+            if (e.key === ']') ctrlChar = '\x1D';        // GS — Ctrl+]
+            else if (e.key === '^') ctrlChar = '\x1E';   // RS — Ctrl+Shift+6
+            else if (e.key === '\\') ctrlChar = '\x1C';  // FS — Ctrl+\
+            else if (e.key === '_') ctrlChar = '\x1F';   // US — Ctrl+Shift+-
+
+            if (ctrlChar) {
+                e.preventDefault();
+                this.scanInput += ctrlChar;
+            }
+        },
+
         /**
          * Process scanned part
          */
@@ -249,11 +270,29 @@ function stockApp() {
 
             // Handle ANSI MH10.8.2 format: [)>06P<part>...
             if (raw.startsWith('[)>06')) {
-                // Extract part number - it's after [)>06P and before the next field marker
+                // If GS/RS separators survived, parse field-by-field — unambiguous.
+                const sepRegex = /[\x1D\x1E]/g;
+                const fields = raw.split(sepRegex);
+
+                if (fields.length > 1) {
+                    for (const field of fields) {
+                        if (!field) continue;
+                        if (field.startsWith('30P')) {
+                            part_code = cleanPartCode(field.substring(3));
+                        } else if (field.startsWith('1P')) {
+                            if (!part_code) part_code = cleanPartCode(field.substring(2));
+                        } else if (/^Q\d+$/.test(field)) {
+                            quantity = parseInt(field.substring(1));
+                        }
+                    }
+                    return { part_code, quantity };
+                }
+
+                // Separators stripped (HTML <input> drops control chars).
+                // Extract part number after [)>06P, up to next explicit field marker.
                 if (raw.length > 6 && raw[5] === 'P') {
                     const afterP = raw.substring(6);
 
-                    // Find the next explicit field marker (1P or 30P)
                     const markers = ['1P', '30P'];
                     let endIdx = afterP.length;
 
@@ -267,8 +306,9 @@ function stockApp() {
                     part_code = cleanPartCode(afterP.substring(0, endIdx));
                 }
 
-                // Extract quantity after Q
-                const qMatch = raw.match(/Q(\d+)/);
+                // Lazy-match Q digits, stopping at the next data identifier
+                // (e.g. 11Z, 12Z, 20Z, 1T, 9D, 4L) or end-of-string.
+                const qMatch = raw.match(/Q(\d+?)(?=\d{0,2}[A-Z]|$)/);
                 if (qMatch) {
                     quantity = parseInt(qMatch[1]);
                 }
@@ -341,6 +381,14 @@ function stockApp() {
 
                 const data = await response.json();
 
+                // Server error → do NOT treat as "not found" or we'll re-queue
+                // a part that was already imported and loop forever.
+                if (!response.ok || data.success === false) {
+                    const stage = data.stage ? ` [${data.stage}]` : '';
+                    this.log('error', `✖ Search failed${stage}: ${data.error || response.statusText}`);
+                    return;
+                }
+
                 if (data.success && data.found) {
                     // Part found
                     this.currentPart = data.part_info;
@@ -528,8 +576,21 @@ function stockApp() {
                 const data = await response.json();
 
                 if (data.success) {
-                    this.pendingParts.push(data.pending_part);
-                    this.log('info', `📋 Added ${partCode} to import queue - continue scanning`);
+                    if (data.already_queued) {
+                        // Update local copy so qty/location reflect latest scan
+                        const idx = this.pendingParts.findIndex(p => p.part_code === partCode);
+                        if (idx >= 0) {
+                            this.pendingParts[idx] = data.pending_part;
+                        } else {
+                            this.pendingParts.push(data.pending_part);
+                        }
+                        this.log('info', `↻ ${partCode} already in import queue (updated qty)`);
+                    } else {
+                        this.pendingParts.push(data.pending_part);
+                        this.log('info', `📋 Added ${partCode} to import queue - continue scanning`);
+                    }
+                } else {
+                    this.log('error', `✖ Queue rejected: ${data.error || 'unknown error'}`);
                 }
             } catch (error) {
                 this.log('error', `✖ Error queuing import: ${error.message}`);

src/stocktool/web/templates/index.html

@@ -103,6 +103,7 @@
                 <input
                     type="text"
                     x-model="scanInput"
+                    @keydown="onScanKeydown($event)"
                     @keyup.enter="processScan"
                     placeholder="Scan part barcode or enter part code..."
                     class="flex-1 px-4 py-3 text-lg bg-gray-700 border border-gray-600 rounded-lg focus:ring-2 focus:ring-blue-500 focus:border-transparent"