DioException [unknown]: null

[choim4389]

Package

dio

Version

5.8.0

Operating-System

Android, iOS

Adapter

Default Dio

Output of flutter doctor -v

[✓] Flutter (Channel stable, 3.27.2, on macOS 14.5 23F79 darwin-arm64, locale
    ko-KR)
    • Flutter version 3.27.2 on channel stable at
      /Users/macan/.asdf/installs/flutter/3.27.2-stable
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision 68415ad1d9 (7 weeks ago), 2025-01-13 10:22:03 -0800
    • Engine revision e672b006cb
    • Dart version 3.6.1
    • DevTools version 2.40.2

[✓] Android toolchain - develop for Android devices (Android SDK version
    34.0.0)
    • Android SDK at /Users/macan/Library/Android/sdk
    • Platform android-35, build-tools 34.0.0
    • ANDROID_HOME = /Users/macan/Library/Android/sdk
    • Java binary at: /Applications/Android
      Studio.app/Contents/jbr/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build
      17.0.7+0-17.0.7b1000.6-10550314)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS (Xcode 16.0)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Build 16A242d
    • CocoaPods version 1.16.2

[✓] Chrome - develop for the web
    • Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome

[✓] Android Studio (version 2023.1)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/6351-dart
    • Java version OpenJDK Runtime Environment (build
      17.0.7+0-17.0.7b1000.6-10550314)

[✓] IntelliJ IDEA Ultimate Edition (version 2024.3.3)
    • IntelliJ at /Applications/IntelliJ IDEA.app
    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/6351-dart

[✓] VS Code (version 1.96.2)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.94.0

[✓] Connected device (4 available)
    • SM S928N (mobile)               • R3CWC0MBFQP           • android-arm64
      • Android 14 (API 34)
    • macOS (desktop)                 • macos                 • darwin-arm64
      • macOS 14.5 23F79 darwin-arm64
    • Mac Designed for iPad (desktop) • mac-designed-for-ipad • darwin
      • macOS 14.5 23F79 darwin-arm64
    • Chrome (web)                    • chrome                •
      web-javascript • Google Chrome 133.0.6943.142
    ! Error: Browsing on the local area network for iPhone (4). Ensure the
      device is unlocked and attached with a cable or associated with the
      same local area network as this Mac.
      The device must be opted into Developer Mode to connect wirelessly.
      (code -27)

[✓] Network resources
    • All expected network resources are available.

Dart Version

3.6.1

Steps to Reproduce

initialize firebase crashlytics

PlatformDispatcher.instance.onError = (error, stack) {
    FirebaseCrashlytics.instance.recordError(error, stack, fatal: true);
    return true;
  };

then create dio client.

Expected Result

no exception logged

Actual Result

In crashlytics, DioException [unknown]: null is always logged at the beginning, even when no request is made.

[buthmathearo]

This happened to me when I tried to call 2 APIs at same time. This is the error message:
DioException [unknown]: null
Error: HttpException: Content size below specified contentLength. 0 bytes written but expected 125

For example:
void initState() {
_getAppInfo(); // Call get app info API in the background.
_getAccountInfo(); // Call get user account info API in the background.
}

Adding some delay between the _getAppInfo() and _getAccountInfo() will temporarily fix this. But it's not a good option.

*** Update ****
In my case, the issue is from the certificate_pinning_httpclient package. There is a bug in CertificatePinningHttpClient.openUrl () when a race condition occurs.

[apurva010]

@choim4389 @buthmathearo
Did you guys find a solution for this? I'm encountering this error quite frequently.

I'm working on a desktop application where an API call is triggered every time the user switches tabs from the drawer. However, for one specific tab, two API calls occur—one for the tab switch and another to fetch a listing when that tab is selected. For all other tabs, only a single API call is made upon switching.

Any insights on resolving this issue would be greatly appreciated!

Error is as below:

DioException [unknown]: null
Error: HttpException: Connection closed before full header was received, uri = {API URL}

[AlexV525]

@choim4389 Please provide the minimal runnable reproducible example.