Solution to package 'php5-curl' has no installation candidate

Solution to this issue arise when you're going to install php5-curl in ubuntu 14.04 Trusty Tahr with

sudo apt-get install php5-curl

is adding a repository that containing php5-curl.

Ondřej Surý's php5 repository is coming to your help now.
https://launchpad.net/~ondrej/+archive/ubuntu/php5

Add Ondrej's repository to your system by

sudo add-apt-repository ppa:ondrej/php5

And then run a update

sudo apt-get update

then you can intall php5-curl

sudo apt-get install php5-curl

run apache restart to make sure your server is working fine with php5-curl

sudo service apache2 restart