Composer Content-Length Mismatch

Just change the composer default repo url:

composer config -g repo.packagist composer https://packagist.org
composer config -g github-protocols https ssh

It changes or sets the packagist repo to be used by https only.

This fixes any issues with local composer.json files too. No need to mess around with the composer.json file localy or global.

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).