URL的Ruby on Rails和JSON解析器 [英] Ruby on Rails and JSON parser from URL

问题描述

我使用'gem json'，并且需要从某些 url 中加载JSON数据，例如:

I use 'gem json' and need load JSON data from some url, for example:

"http://locallhost:3000/qwerty/give_json.json"与

{"one":"Omg","two":125,"three":"Hu"}

我有Rails应用

class QwertyController < ApplicationController
    require 'json'

    def get_json
        source = "http://localhost:3000/qwerty/give_json.json"
        @data = JSON.parse(JSON.load(source))
    end
end

我收到错误

JSON::ParserError in QwertyController#get_json
795: unexpected token at 'http://localhost:3000/qwerty/give_json.json'

在字符串中:@data = JSON.parse(JSON.load(source))

In string: @data = JSON.parse(JSON.load(source))

怎么了?如何获取和解析JSON数据?我尝试@data ["one"] ...

What is the matter? How can I get JSON data and parse it? I try @data["one"] ...

推荐答案

JSON.load根据文档

http://www.ruby -doc.org/stdlib-1.9.3/libdoc/json/rdoc/JSON.html#method-i-load

[17] pry(main)> {hello: "World"}.to_json
=> "{\"hello\":\"World\"}"
[18] pry(main)> JSON.load(_)
=> {"hello"=>"World"}

您要给它提供一个URL字符串，这就是为什么您遇到错误的原因.您可以使用open-uri从URL中获取数据，然后再通过JSON进行解析，就像这样...

You're giving it a String that is a URL and that's why you're getting an error. You can use open-uri to fetch the data from the URL to then be parsed by JSON like so...

[22] pry(main)> require 'open-uri'
=> false
[23] pry(main)> JSON.load(open("https://api.github.com"))
=> {"current_user_url"=>"https://api.github.com/user",
 "authorizations_url"=>"https://api.github.com/authorizations",
 "emails_url"=>"https://api.github.com/user/emails",
 "emojis_url"=>"https://api.github.com/emojis",
 "events_url"=>"https://api.github.com/events",
 "feeds_url"=>"https://api.github.com/feeds",
 "following_url"=>"https://api.github.com/user/following{/target}",
 "gists_url"=>"https://api.github.com/gists{/gist_id}",
 "hub_url"=>"https://api.github.com/hub"}

注意

open返回StringIO对象，该对象响应read返回JSON数据. JSON.load将数据转换为要使用的哈希.

open returns a StringIO object which responds to read returning the JSON data. JSON.load turns the data into a hash to be used.

要解析JSON字符串，您可以使用JSON.load或JSON.parse

To parse the JSON string you can either use JSON.load or JSON.parse

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