我使用的是Ruby on Rails 3.1预版本。我喜欢使用PostgreSQL,但问题是安装pg gem。它给了我以下错误:

$ gem install pg
Building native extensions.  This could take a while...
ERROR:  Error installing pg:
    ERROR: Failed to build gem native extension.

        /home/u/.rvm/rubies/ruby-1.9.2-p0/bin/ruby extconf.rb
checking for pg_config... no
No pg_config... trying anyway. If building fails, please try again with
 --with-pg-config=/path/to/pg_config
checking for libpq-fe.h... no
Can't find the 'libpq-fe.h header
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of
necessary libraries and/or headers.  Check the mkmf.log file for more
details.  You may need configuration options.

Provided configuration options:
    --with-opt-dir
    --without-opt-dir
    --with-opt-include
    --without-opt-include=${opt-dir}/include
    --with-opt-lib
    --without-opt-lib=${opt-dir}/lib
    --with-make-prog
    --without-make-prog
    --srcdir=.
    --curdir
    --ruby=/home/u/.rvm/rubies/ruby-1.9.2-p0/bin/ruby
    --with-pg
    --without-pg
    --with-pg-dir
    --without-pg-dir
    --with-pg-include
    --without-pg-include=${pg-dir}/include
    --with-pg-lib
    --without-pg-lib=${pg-dir}/lib
    --with-pg-config
    --without-pg-config
    --with-pg_config
    --without-pg_config
    Gem files will remain installed in /home/u/.rvm/gems/ruby-1.9.2-p0/gems/pg-0.11.0 for inspection.
    Results logged to /home/u/.rvm/gems/ruby-1.9.2-p0/gems/pg-0.11.0/ext/gem_make.out

我怎么解决这个问题?


当前回答

在OS X和MacPorts上,PostgreSQL不再需要-devel包。安装pg gem的步骤如下:

~ > sudo port install postgresql-devel
...
Error: postgresql-devel has been replaced by postgresql91; please install that port instead
~ > gem install pg -v '0.17.1' -- --with-pg-config=/opt/local/lib/postgresql95/bin/pg_config

参见这篇文章。

其他回答

只是缺少libpq-fe.h的问题

在ubuntu上,我们只需要运行: Sudo apt-get安装libpq-dev

上面的命令将安装一个新的包libpq-dev,之后你可以再次执行bundle install来继续你的包安装。

在Mac上,我用下面的代码解决了这个问题:

gem install pg -v '0.18.4' -- --with-pg-config=/Applications/Postgres.app/Contents/Versions/9.4/bin/pg_config

Ubuntu 20.04.1 LTS,这似乎对我有用:

sudo apt-get install ruby ruby-dev libpqxx-dev libpq-fe-dev libpq-dev 
sudo gem install pg -- --with-pg-config=/usr/include/postgresql/pg_config --with-pg-include=/usr/include/postgresql/

郑重声明:

Ruby on Rails 4应用程序在OS X与PostgresApp(在这种情况下需要0.17.1版本-有点老项目):

gem install pg -v '0.17.1' -- --with-pg-config=/Applications/Postgres.app/Contents/Versions/9.3/bin/pg_config

我找到了这个答案,这是唯一一个对我有用的(Mac OS)——在研究了大约两天之后:

$ sudo su

$ env ARCHFLAGS="-arch x86_64" gem install pg

Building native extensions.  This could take a while...
Successfully installed pg-0.11.0
1 gem installed
Installing ri documentation for pg-0.11.0...
Installing RDoc documentation for pg-0.11.0...

参见堆栈溢出问题无法找到PostgreSQL客户端库(libpq)。