2014-12-13

HTTP客户端Httpotion

步骤

本文描述如何使用Elixir的httpotion模块调用豆瓣图书API获取图书信息.

root@7bf32c349b69:~# mix new douban_book_api_v2
* creating README.md
* creating .gitignore
* creating mix.exs
* creating config
* creating config/config.exs
* creating lib
* creating lib/douban_book_api_v2.ex
* creating test
* creating test/test_helper.exs
* creating test/douban_book_api_v2_test.exs

Your mix project was created successfully.
You can use mix to compile it, test it, and more:

    cd douban_book_api_v2
    mix test

Run `mix help` for more commands.

进入刚刚创建的目录douban_book_api_v2,编辑mix.exs,增加依赖模块:

修改函数deps为:

defp deps do
    [
        {:ibrowse, github: "cmullaparthi/ibrowse", tag: "v4.1.0"},
        {:jiffy, github: "davisp/jiffy"},
        {:httpotion, "~> 0.2.0"}
    ]
end

然后执行如下命令,下载依赖模块:

# cd douban_book_api_v2
# mix deps.get

注意很多依赖模块托管在Amazon S3上,可能被墙, 可使用如下命令穿墙:

export HTTP_PROXY=http://192.168.8.188:8580
export HTTPS_PROXY=https://192.168.8.188:8580

然后编译:

# mix compile

接着进入iex(Elixir交互式SHELL):

# iex -S mix

示例代码

https://github.com/developerworks/douban_book_api_v2

参考资料

1. https://github.com/myfreeweb/httpotion
2. http://developers.douban.com/wiki/?title=book_v2#get_book
3. https://api.douban.com/v2/book/1041007
4. http://learnxinyminutes.com/docs/zh-cn/elixir-cn/

修订记录

• 2014-12-14 13:30
  使用ej模块获取由jiffy, mochijson2, 或 ejson 返回的Erlang terms

# 把响应体解码为Erlang term
json = :jiffy.decode response.body
# 通过ej模块访问Erlang term
:ej.get({"author"}, josn)

iex(21)> :ej.get {"images", "small"}, json
"http://img3.douban.com/spic/s1990480.jpg"
iex(22)> :ej.get {"images", "large"}, json
"http://img3.douban.com/lpic/s1990480.jpg"
iex(23)> :ej.get {"images", "medium"}, json
"http://img3.douban.com/mpic/s1990480.jpg"
iex(24)> :ej.get {"images", "medium"}, json
"http://img3.douban.com/mpic/s1990480.jpg"
iex(25)> :ej.get {"images", "tags", 1}, json
:undefined
iex(26)> :ej.get {"images", "tags"}, json
:undefined
iex(27)> :ej.get {"tags"}, json
[{[{"count", 13368}, {"name", "哈利波特"}, {"title", "哈利波特"}]},
 {[{"count", 10741}, {"name", "J.K.罗琳"}, {"title", "J.K.罗琳"}]},
 {[{"count", 8892}, {"name", "魔幻"}, {"title", "魔幻"}]},
 {[{"count", 7741}, {"name", "小说"}, {"title", "小说"}]},
 {[{"count", 6536}, {"name", "英国"}, {"title", "英国"}]},
 {[{"count", 4591}, {"name", "外国文学"}, {"title", "外国文学"}]},
 {[{"count", 3871}, {"name", "哈利·波特"}, {"title", "哈利·波特"}]},
 {[{"count", 3871}, {"name", "哈利・波特"}, {"title", "哈利・波特"}]}]
iex(28)> :ej.get {"tags", 1}, json
{[{"count", 13368}, {"name", "哈利波特"}, {"title", "哈利波特"}]}
iex(29)> :ej.get {"tags", 1, "count"}, json
13368
iex(30)> :ej.get {"tags", 1, "name"}, json
"哈利波特"
iex(31)> :ej.get {"tags", 1, "title"}, json
"哈利波特"
iex(32)> :ej.get {"tags", 2, "title"}, json
"J.K.罗琳"
iex(33)> :ej.get {"tags", 3, "title"}, json
"魔幻"
iex(34)> :ej.get {"tags", 3, "count"}, json
8892

Elixir

Elixir, Httpotion