iOS Cocoapods更新，pod update 失败

最近公司开始新的项目，然后就开始搭建项目。在使用CocoaPods的时候碰到一些使用问题。查阅一些资料，整理了一下。

在2018.02.23以后， Mac默认的Ruby运行环境下，在终端执行pod setup或pod update时会有如下报错

 -- [!] Failed to connect to GitHub to update the CocoaPods/Specs specs repo - Please check if you are offline, or that GitHub is down

原因：weak-cryptographic-standards-removed

https://blog.github.com/2018-02-23-weak-cryptographic-standards-removed/

这样我们就需要更新openssl、Ruby以及CocoaPods。在终端输入如下代码

$ which openssl

/usr/bin/openssl

$ openssl version

OpenSSL 0.9.8zh 14 Jan 2016

$ /usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

$ brew update

$ brew install openssl

$ brew upgrade openssl

$ echo 'export PATH="/usr/local/opt/openssl/bin:$PATH"' >> ~/.bash_profile

$ source ~/.bash_profile

$ which openssl

/usr/local/opt/openssl/bin/openssl

$ openssl version

OpenSSL 1.0.2n  7 Dec 2017

$ brew install rbenv ruby-build

$ echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.bash_profile

$ echo 'if which rbenv > /dev/null; then eval "$(rbenv init -)"; fi' >> ~/.bash_profile

$ source ~/.bash_profile

$ rbenv install --list

Available versions:

  1.8.5-p52

  1.8.5-p113

  1.8.5-p114

    ...

  2.5.0-rc1

  2.5.0

  2.6.0-dev

$ rbenv install 2.5.0

$ rbenv versions

* system (set by /Users/username/.rbenv/version)

  2.5.0

$ ruby --version

ruby 2.0.0p648 (2015-12-16 revision 53162) [universal.x86_64-darwin16]

$ rbenv global 2.5.0

$ rbenv versions

  system

* 2.5.0 (set by /Users/username/.rbenv/version)

$ ruby --version

ruby 2.5.0p0 (2017-12-25 revision 61468) [x86_64-darwin16]

$ gem install cocoapods -n /usr/local/bin

$ which pod

/usr/local/bin/pod

$ pod --version

1.4.0

这些确认完毕，再执行：

$ pod update

等待更新完成。

参考资料：ttps://qiita.com/satoshi-iwaki/items/ed2c267127dcc80baa21