Your requirements could not be resolved: failed to open stream: Permission denied - composer-php

Question

I Need to install DomPDf in my Project. So, i add "barryvdh/laravel-dompdf": "v0.7.0", to composer require block. when i update composer display following Errors. Whats my Mistakes.... Please Specify to me..
Terminal Errors
Your requirements could not be resolved to an installable set of packages.
Problem 1
- dompdf/dompdf v0.7.0-beta3 requires phenx/php-font-lib 0.4.* -> no matching package found.
- dompdf/dompdf v0.7.0-beta2 requires phenx/php-font-lib 0.4.* -> no matching package found.
- dompdf/dompdf v0.7.0-beta requires phenx/php-font-lib 0.3.* -> no matching package found.
- dompdf/dompdf v0.7.0 requires phenx/php-font-lib 0.4.* -> no matching package found.
- dompdf/dompdf 0.7.x-dev requires phenx/php-font-lib 0.5.* -> no matching package found.
- barryvdh/laravel-dompdf v0.7.0 requires dompdf/dompdf ^0.7 -> satisfiable by dompdf/dompdf[0.7.x-dev, v0.7.0, v0.7.0-beta, v0.7.0-beta2, v0.7.0-beta3].
- Installation request for barryvdh/laravel-dompdf v0.7.0 -> satisfiable by barryvdh/laravel-dompdf[v0.7.0].
Potential causes:
- A typo in the package name
- The package is not available in a stable-enough version according to your minimum-stability setting
see <https://getcomposer.org/doc/04-schema.md#minimum-stability> for more details.
My Composer Code
{
"name": "laravel/laravel",
"description": "The Laravel Framework.",
"keywords": ["framework", "laravel"],
"minimum-stability" : "dev",
"prefer-stable": true,
"license": "MIT",
"type": "project",
"require": {
"php": ">=5.6.4",
"barryvdh/laravel-debugbar": "^2.3",
"barryvdh/laravel-dompdf": "v0.7.0",
"laravel/framework": "5.4.*",
"laravel/tinker": "~1.0",
"uxweb/sweet-alert": "^1.4"
},
"require-dev": {
"fzaninotto/faker": "~1.4",
"mockery/mockery": "0.9.*",
"phpunit/phpunit": "~5.0"
},
"autoload": {
"classmap": [
"database"
],
"psr-4": {
"App\\": "app/"
}
}
I've also tried:
composer require barryvdh/laravel-dompdf
but it display following error:
Error : Using version ^0.8.0 for barryvdh/laravel-dompdf ./composer.json has been updated Loading composer repositories with package information
Updating dependencies (including require-dev)
file_put_contents(/home/w3cert/.composer/cache/repo/https---‌​packagist.org/p-prov‌​ider-2017-01.json): failed to open stream: Permission denied
packagist.org could not be fully loaded, package information was loaded from the local cache and may be out of date
Your requirements could not be resolved to an installable set of packages.

Answer 1

Since you've got the Permission denied error when running composer require barryvdh/laravel-dompdf, this is the command which should fix them:
chown -R $USER ~/.composer
or:
sudo chown -R $USER ~/.composer
Then clear the Composer caches:
composer clear
After than try to avoid running composer command with sudo to not break the file permissions.
If there is still any problem, in order to troubleshoot, run the following shell command:
composer diagnose

Answer 2

Why don't you try to install it from the command line
composer require barryvdh/laravel-dompdf
please delete this line from composer.json before installation.
"barryvdh/laravel-dompdf": "v0.7.0"
Anyway the current version of laravel-dompdf:(v0.8.0)

Answer 3

The installation should work with the current version of dompdf
"barryvdh/laravel-dompdf": "^0.8.0"