Composer Content-Length Mismatch

Sometimes when I run composer update to upgrade the laravel project, a content-length mismatch exception might occur. Finally, I get this is because of the terrible firewall in China: the DNS was poisoned. So, if you are like me, could there be a way to fix it out?

First, run:

composer config --list --global          //this will get the composer home path.
[home] /root/.composer                   //it's my composer home path.

And then, edit the config.json, make it like this:

{
  "config": {
    "github-protocols": [
      "https"
    ]
  },
  "repositories": {
    "packagist.org": {
      "type": "composer",
      "url": "https://packagist.org"
    }
  }
}

It will make the packagist connection force https. And also you could config the composer.json in your project, this is a laravel sample would be look like:

{
  "name": "laravel/laravel",
  "description": "The Laravel Framework.",
  "keywords": [
    "framework",
    "laravel"
  ],
  "license": "MIT",
  "type": "project",
  "require": {
    "php": ">=5.5.9",
    "laravel/framework": "5.2.*"
  },
  "config": {
    "preferred-install": "dist"
  },
  "repositories": {
    "packagist.org": {
      "type": "composer",
      "url": "https://packagist.org"
    }
  }
}

Update

Before Composer v1.2.3 the repository key for packagist was "packagist". In v1.2.3 it was changed to "packagist.org" (see commit e38ebef).