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feat: support concurrent chunk uploads #313

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562f956
feat: support concurrent chunk uploads
TorstenDittmann May 21, 2026
23fc93d
Commit from GitHub Actions (Format and push)
TorstenDittmann May 21, 2026
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2 changes: 1 addition & 1 deletion README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -19,7 +19,7 @@ Add this to your package's `pubspec.yaml` file:

```yml
dependencies:
appwrite: ^24.1.1
appwrite: ^24.2.0
```

You can install packages from the command line:
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4 changes: 2 additions & 2 deletions docs/examples/avatars/get-screenshot.md
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Original file line number Diff line number Diff line change
Expand Up @@ -22,7 +22,7 @@ Uint8List bytes = await avatars.getScreenshot(
userAgent: 'Mozilla/5.0 (iPhone; CPU iPhone OS 14_0 like Mac OS X) AppleWebKit/605.1.15', // optional
fullpage: true, // optional
locale: 'en-US', // optional
timezone: enums.Timezone.americaNewYork, // optional
timezone: enums.Timezone.africaAbidjan, // optional
latitude: 37.7749, // optional
longitude: -122.4194, // optional
accuracy: 100, // optional
Expand Down Expand Up @@ -53,7 +53,7 @@ FutureBuilder(
userAgent:'Mozilla/5.0 (iPhone; CPU iPhone OS 14_0 like Mac OS X) AppleWebKit/605.1.15' , // optional
fullpage:true , // optional
locale:'en-US' , // optional
timezone: enums.Timezone.americaNewYork, // optional
timezone: enums.Timezone.africaAbidjan, // optional
latitude:37.7749 , // optional
longitude:-122.4194 , // optional
accuracy:100 , // optional
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114 changes: 92 additions & 22 deletions lib/src/client_browser.dart
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Original file line number Diff line number Diff line change
Expand Up @@ -40,7 +40,7 @@ class ClientBrowser extends ClientBase with ClientMixin {
'x-sdk-name': 'Flutter',
'x-sdk-platform': 'client',
'x-sdk-language': 'flutter',
'x-sdk-version': '24.1.1',
'x-sdk-version': '24.2.0',
'X-Appwrite-Response-Format': '1.9.5',
};

Expand Down Expand Up @@ -207,6 +207,7 @@ class ClientBrowser extends ClientBase with ClientMixin {
}

var offset = 0;
String? uploadId;
if (idParamName.isNotEmpty) {
//make a request to check if a file already exists
try {
Expand All @@ -217,40 +218,109 @@ class ClientBrowser extends ClientBase with ClientMixin {
);
final int chunksUploaded = res.data['chunksUploaded'] as int;
offset = chunksUploaded * chunkSize;
uploadId = res.data['\$id'] ?? params[idParamName]?.toString();
} on AppwriteException catch (_) {}
}

while (offset < size) {
if (offset >= size) {
return res;
}

final totalChunks = (size / chunkSize).ceil();

Future<Response> uploadChunk(
int index, int start, int end, String? id) async {
List<int> chunk = [];
final end = min(offset + chunkSize, size);
chunk = file.bytes!.getRange(offset, end).toList();
params[paramName] = http.MultipartFile.fromBytes(
chunk = file.bytes!.getRange(start, end).toList();

final chunkParams = Map<String, dynamic>.from(params);
chunkParams[paramName] = http.MultipartFile.fromBytes(
paramName,
chunk,
filename: file.filename,
);
headers['content-range'] =
'bytes $offset-${min<int>((offset + chunkSize - 1), size - 1)}/$size';
res = await call(
final chunkHeaders = Map<String, String>.from(headers);
if (id != null && id.isNotEmpty) {
chunkHeaders['x-appwrite-id'] = id;
}
chunkHeaders['content-range'] = 'bytes $start-${end - 1}/$size';

return call(
HttpMethod.post,
path: path,
headers: headers,
params: params,
headers: chunkHeaders,
params: chunkParams,
);
offset += chunkSize;
if (offset < size) {
headers['x-appwrite-id'] = res.data['\$id'];
}
Comment on lines +231 to +254

@greptile-apps greptile-apps Bot May 21, 2026

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P2 Unused index parameter in uploadChunk

The index parameter is accepted by uploadChunk in both client_browser.dart and client_io.dart but is never referenced in either function body. All positioning is done via start/end, so the parameter appears to be dead code. Remove it or document its intended use to avoid confusion.


final firstStart = offset;
final firstEnd = min(firstStart + chunkSize, size);
final firstIndex = firstStart ~/ chunkSize;
res = await uploadChunk(firstIndex, firstStart, firstEnd, uploadId);
uploadId = res.data['\$id'] ?? uploadId;

var completedChunks = firstIndex + 1;
var uploadedBytes = firstEnd;
var lastResponse = res;

bool isUploadComplete(Response response) {
final chunksUploaded = response.data['chunksUploaded'];
final chunksTotal = response.data['chunksTotal'] ?? totalChunks;
return chunksUploaded is num &&
chunksTotal is num &&
chunksUploaded >= chunksTotal;
}

final progress = UploadProgress(
$id: uploadId ?? '',
progress: min(uploadedBytes, size) / size * 100,
sizeUploaded: min(uploadedBytes, size),
chunksTotal: totalChunks,
chunksUploaded: completedChunks,
);
onProgress?.call(progress);

final chunks = <Map<String, int>>[];
for (var start = firstEnd; start < size; start += chunkSize) {
final end = min(start + chunkSize, size);
chunks.add({
'index': start ~/ chunkSize,
'start': start,
'end': end,
});
}

var nextChunk = 0;
Future<void> uploadNext() async {
while (nextChunk < chunks.length) {
final chunk = chunks[nextChunk++];
final chunkResponse = await uploadChunk(
chunk['index']!,
chunk['start']!,
chunk['end']!,
uploadId,
);
completedChunks++;
uploadedBytes += chunk['end']! - chunk['start']!;
if (isUploadComplete(chunkResponse)) {
lastResponse = chunkResponse;
}
Comment on lines +305 to +307

@greptile-apps greptile-apps Bot May 21, 2026

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P2 lastResponse falls back to the first-chunk response if the server never signals completion

lastResponse is only updated inside uploadNext when isUploadComplete returns true. If every concurrent chunk response has null or a non-num chunksUploaded field (e.g., a transient server regression), lastResponse stays as the first chunk's Response—which has stale metadata such as chunksUploaded: 1. The caller has no way to distinguish this from a genuinely incomplete upload. The old sequential loop always returned the last chunk's response regardless of field values.


final progress = UploadProgress(
$id: uploadId ?? '',
progress: min(uploadedBytes, size) / size * 100,
sizeUploaded: min(uploadedBytes, size),
chunksTotal: totalChunks,
chunksUploaded: completedChunks,
);
onProgress?.call(progress);
}
final progress = UploadProgress(
$id: res.data['\$id'] ?? '',
progress: min(offset, size) / size * 100,
sizeUploaded: min(offset, size),
chunksTotal: res.data['chunksTotal'] ?? 0,
chunksUploaded: res.data['chunksUploaded'] ?? 0,
);
onProgress?.call(progress);
}
return res;

final concurrency = min(8, chunks.length);
await Future.wait(List.generate(concurrency, (_) => uploadNext()));

return lastResponse;
}

@override
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126 changes: 97 additions & 29 deletions lib/src/client_io.dart
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Original file line number Diff line number Diff line change
Expand Up @@ -58,7 +58,7 @@ class ClientIO extends ClientBase with ClientMixin {
'x-sdk-name': 'Flutter',
'x-sdk-platform': 'client',
'x-sdk-language': 'flutter',
'x-sdk-version': '24.1.1',
'x-sdk-version': '24.2.0',
'X-Appwrite-Response-Format': '1.9.5',
};

Expand Down Expand Up @@ -328,6 +328,7 @@ class ClientIO extends ClientBase with ClientMixin {
}

var offset = 0;
String? uploadId;
if (idParamName.isNotEmpty) {
//make a request to check if a file already exists
try {
Expand All @@ -338,52 +339,119 @@ class ClientIO extends ClientBase with ClientMixin {
);
final int chunksUploaded = res.data['chunksUploaded'] as int;
offset = chunksUploaded * chunkSize;
uploadId = res.data['\$id'] ?? params[idParamName]?.toString();
} on AppwriteException catch (_) {}
}

RandomAccessFile? raf;
// read chunk and upload each chunk
if (iofile != null) {
raf = await iofile.open(mode: FileMode.read);
if (offset >= size) {
return res;
}

while (offset < size) {
final totalChunks = (size / chunkSize).ceil();

Future<Response> uploadChunk(
int index, int start, int end, String? id) async {
List<int> chunk = [];
if (file.bytes != null) {
final end = min(offset + chunkSize, size);
chunk = file.bytes!.getRange(offset, end).toList();
chunk = file.bytes!.getRange(start, end).toList();
} else {
raf!.setPositionSync(offset);
chunk = raf.readSync(chunkSize);
final raf = await iofile!.open(mode: FileMode.read);
try {
await raf.setPosition(start);
chunk = await raf.read(end - start);
} finally {
await raf.close();
}
}
params[paramName] = http.MultipartFile.fromBytes(

final chunkParams = Map<String, dynamic>.from(params);
chunkParams[paramName] = http.MultipartFile.fromBytes(
paramName,
chunk,
filename: file.filename,
);
headers['content-range'] =
'bytes $offset-${min<int>((offset + chunkSize - 1), size - 1)}/$size';
res = await call(
final chunkHeaders = Map<String, String>.from(headers);
if (id != null && id.isNotEmpty) {
chunkHeaders['x-appwrite-id'] = id;
}
chunkHeaders['content-range'] = 'bytes $start-${end - 1}/$size';

return call(
HttpMethod.post,
path: path,
headers: headers,
params: params,
headers: chunkHeaders,
params: chunkParams,
);
offset += chunkSize;
if (offset < size) {
headers['x-appwrite-id'] = res.data['\$id'];
}

final firstStart = offset;
final firstEnd = min(firstStart + chunkSize, size);
final firstIndex = firstStart ~/ chunkSize;
res = await uploadChunk(firstIndex, firstStart, firstEnd, uploadId);
uploadId = res.data['\$id'] ?? uploadId;

var completedChunks = firstIndex + 1;
var uploadedBytes = firstEnd;
var lastResponse = res;

bool isUploadComplete(Response response) {
final chunksUploaded = response.data['chunksUploaded'];
final chunksTotal = response.data['chunksTotal'] ?? totalChunks;
return chunksUploaded is num &&
chunksTotal is num &&
chunksUploaded >= chunksTotal;
}

final progress = UploadProgress(
$id: uploadId ?? '',
progress: min(uploadedBytes, size) / size * 100,
sizeUploaded: min(uploadedBytes, size),
chunksTotal: totalChunks,
chunksUploaded: completedChunks,
);
onProgress?.call(progress);

final chunks = <Map<String, int>>[];
for (var start = firstEnd; start < size; start += chunkSize) {
final end = min(start + chunkSize, size);
chunks.add({
'index': start ~/ chunkSize,
'start': start,
'end': end,
});
}

var nextChunk = 0;
Future<void> uploadNext() async {
while (nextChunk < chunks.length) {
final chunk = chunks[nextChunk++];
final chunkResponse = await uploadChunk(
chunk['index']!,
chunk['start']!,
chunk['end']!,
uploadId,
);
completedChunks++;
uploadedBytes += chunk['end']! - chunk['start']!;
if (isUploadComplete(chunkResponse)) {
lastResponse = chunkResponse;
}

final progress = UploadProgress(
$id: uploadId ?? '',
progress: min(uploadedBytes, size) / size * 100,
sizeUploaded: min(uploadedBytes, size),
chunksTotal: totalChunks,
chunksUploaded: completedChunks,
);
onProgress?.call(progress);
}
final progress = UploadProgress(
$id: res.data['\$id'] ?? '',
progress: min(offset, size) / size * 100,
sizeUploaded: min(offset, size),
chunksTotal: res.data['chunksTotal'] ?? 0,
chunksUploaded: res.data['chunksUploaded'] ?? 0,
);
onProgress?.call(progress);
}
raf?.close();
return res;

final concurrency = min(8, chunks.length);
await Future.wait(List.generate(concurrency, (_) => uploadNext()));

return lastResponse;
}

bool get _customSchemeAllowed => Platform.isWindows || Platform.isLinux;
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2 changes: 1 addition & 1 deletion pubspec.yaml
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Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
name: appwrite
version: 24.1.1
version: 24.2.0
description: Appwrite is an open-source self-hosted backend server that abstracts and simplifies complex and repetitive development tasks behind a very simple REST API
homepage: https://appwrite.io
repository: https://github.com/appwrite/sdk-for-flutter
Expand Down