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Fix upload failures on iOS Safari (load failed)

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iOS Safari kills fetch requests when the app goes to background or
the connection drops during large uploads, producing 'load failed'.
The sync engine was burning through all 5 retries instantly with no
delay, so a transient failure became permanent.

Changes:
- Add AbortController timeout (120s) on upload fetch
- Add exponential backoff between retries (2s, 5s, 10s...60s)
- Increase max retries from 5 to 15 for flaky mobile networks
- Remove 10MB resize step that was re-compressing photos already
  sized at capture time, avoiding extra memory pressure on iOS
- Log photo size with each upload attempt for easier debugging

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
This commit is contained in:
kamaji
2026-02-07 15:31:54 -06:00
parent 0eef9bf2f3
commit 4491531acb
1 changed files with 42 additions and 64 deletions
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102
app/static/js/sync.js
View File

@@ -7,8 +7,11 @@ const Sync = {
currentUsername: null,
isOnline: navigator.onLine,
isSyncing: false,
MAX_RETRIES: 5,
MAX_RETRIES: 15,
VERIFY_DELAY_MS: 800,
UPLOAD_TIMEOUT_MS: 120000,
// Backoff delays in ms per retry attempt
BACKOFF_DELAYS: [0, 2000, 5000, 10000, 15000, 30000, 30000, 60000, 60000, 60000, 60000, 60000, 60000, 60000, 60000],
init(username) {
this.currentUsername = username;
@@ -96,6 +99,19 @@ const Sync = {
continue;
}
// Backoff delay before retry attempts
if (retryCount > 0) {
const backoff = this.BACKOFF_DELAYS[Math.min(retryCount, this.BACKOFF_DELAYS.length - 1)];
console.log('[SYNC] Waiting', backoff + 'ms before retry', retryCount + 1);
await this.delay(backoff);
// Re-check connectivity after waiting
if (!this.isOnline) {
console.log('[SYNC] Lost connection during backoff, stopping');
break;
}
}
await this.uploadPhoto(photo);
}
},
@@ -104,7 +120,9 @@ const Sync = {
const retryCount = photo.retryCount || 0;
try {
console.log('[SYNC] Uploading:', photo.filename, '(attempt', retryCount + 1, 'of', this.MAX_RETRIES + ')');
console.log('[SYNC] Uploading:', photo.filename,
'(' + (photo.blob ? (photo.blob.size / 1024 / 1024).toFixed(1) + 'MB' : 'no blob') + ')',
'attempt', retryCount + 1, 'of', this.MAX_RETRIES);
// Validate blob before attempting upload
if (!photo.blob || !(photo.blob instanceof Blob) || photo.blob.size === 0) {
@@ -116,7 +134,7 @@ const Sync = {
// Prevent page navigation during upload
this._setUploading(true);
// Only check for duplicates on retries (skip on first attempt to reduce latency)
// Check for duplicates on retries (skip on first attempt to reduce latency)
if (retryCount > 0) {
const fullPath = photo.targetPath.replace(/\/$/, '') + '/' + photo.filename;
const alreadyExists = await this.checkFileExists(fullPath);
@@ -134,23 +152,32 @@ const Sync = {
}
}
// Resize if over 10MB
let uploadBlob = photo.blob;
if (uploadBlob.size > 10 * 1024 * 1024) {
console.log('[SYNC] Photo too large (' + (uploadBlob.size / 1024 / 1024).toFixed(1) + 'MB), resizing...');
uploadBlob = await this.resizeImage(uploadBlob, 10 * 1024 * 1024);
console.log('[SYNC] Resized to ' + (uploadBlob.size / 1024 / 1024).toFixed(1) + 'MB');
}
const uploadBlob = photo.blob;
const formData = new FormData();
formData.append('file', uploadBlob, photo.filename);
const uploadUrl = '/api/files/upload?path=' + encodeURIComponent(photo.targetPath);
const uploadResponse = await fetch(uploadUrl, {
// Upload with timeout via AbortController
const controller = new AbortController();
const timeoutId = setTimeout(() => controller.abort(), this.UPLOAD_TIMEOUT_MS);
let uploadResponse;
try {
uploadResponse = await fetch(uploadUrl, {
method: 'POST',
body: formData
body: formData,
signal: controller.signal
});
} catch (fetchErr) {
clearTimeout(timeoutId);
if (fetchErr.name === 'AbortError') {
throw new Error('Upload timed out (' + (this.UPLOAD_TIMEOUT_MS / 1000) + 's)');
}
throw fetchErr;
}
clearTimeout(timeoutId);
if (!uploadResponse.ok) {
let errorMsg = 'Upload failed';
@@ -203,7 +230,7 @@ const Sync = {
} catch (error) {
this._setUploading(false);
console.error('[SYNC] Upload failed:', error, '(attempt', retryCount + 1 + ')');
console.error('[SYNC] Upload failed:', error.message, '(attempt', retryCount + 1 + ')');
await Storage.updatePhoto(photo.id, {
status: 'pending',
retryCount: retryCount + 1,
@@ -213,55 +240,6 @@ const Sync = {
}
},
async resizeImage(blob, maxBytes) {
return new Promise((resolve, reject) => {
const img = new Image();
const url = URL.createObjectURL(blob);
img.onload = () => {
URL.revokeObjectURL(url);
let quality = 0.85;
let scale = 1.0;
const attempt = () => {
const canvas = document.createElement('canvas');
canvas.width = Math.round(img.width * scale);
canvas.height = Math.round(img.height * scale);
const ctx = canvas.getContext('2d');
ctx.drawImage(img, 0, 0, canvas.width, canvas.height);
canvas.toBlob((result) => {
if (!result) {
reject(new Error('Failed to resize image'));
return;
}
if (result.size <= maxBytes || (quality <= 0.4 && scale <= 0.3)) {
resolve(result);
} else {
// Reduce quality first, then scale down
if (quality > 0.5) {
quality -= 0.1;
} else {
scale *= 0.8;
quality = 0.7;
}
attempt();
}
}, 'image/jpeg', quality);
};
attempt();
};
img.onerror = () => {
URL.revokeObjectURL(url);
reject(new Error('Failed to load image for resize'));
};
img.src = url;
});
},
async pruneHistory() {
// Keep only the last 20 completed (verified/failed) entries per user
const completed = await Storage.db.photos