Apache HttpComponents中的cookie匹配策略
目录
1 简介
在clojure中使用clj-http抓取网页时，需要提交自定义cookie,总是不能成功发送，研究一下HttpClient中Cookie的工作方式。
clj-http包装了HttpClient库，对于请求页面时发回的状态可以自动处理，但是需要自己往请求中添加cookie时总是失败，折腾了很久，了解了HttpClient处理Cookie的细节，关于HttpClient中HTTP的状态管理，可以参考HttpClient的
2 示例
从bing获取搜索结果，代码如下：
deps.edn文件如下:
{ :deps { org.clojure/clojure { :mvn/version "1.10.0"}, clj-http { :mvn/version "3.9.1"}, ; http reaver { :mvn/version "0.1.2"} ; jsoup, html parser }} 实际代码：
(require '[clj-http.client :as client])(require '[clj-http.cookies :as cookies])(require '[reaver :as html])(def ua "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:33.0) Gecko/20120101 Firefox/33.0")(def cs (cookies/cookie-store))(def http-header { :headers { "user-agent" ua "accept-charset" "utf-8"} :proxy-host "localhost" ;本地代理,用于测试 :proxy-port 8080 :cookie-store cs :insecure? true})(defn search "搜索关键字kw，返回[{:url :title :desc} ...] kw 为搜索关键字 opt为附加选项: :option http请求额外参数 :max-page 查询的最大页数,默认为3" [kw & [opt]] (let [base-url "https://www.bing.com" option (get opt :option {}) max-page (get opt :max-page 3)] (loop [page 1 url (str base-url "/search?q=" kw) ;这里没有用url编码，仅为演示用 result []] (if (> page max-page) result (let [doc (-> (client/get url (merge http-header option)) :body html/parse) entrys (html/extract-from doc "li.b_algo" [:url :title :desc] "h2 > a" (html/attr "href") "h2 > a" html/text "div > p" html/text) r (apply conj result entrys)] (if-let [next-path (-> (html/select doc "a.sb_pagn" ) (html/attr "href"))] (recur (inc page) (str base-url next-path) r) r))))))(def googles (search "google" { :max-page 3}))(count googles);; => 30(first googles);; => {:url "http://www.google.cn/", :title "Google", :desc "2016-12-8 · google.com.hk 请收藏我们的网址"} 可以看到一页返回10个结果，如果要返回50(bing设置里最大结果数量)，则要设置cookie项： "SRCHHPGUSR" 的值为： "NRSLT=50"
下面添加cookie：
(cookies/clear-cookies cs) ;清除之前请求产生的cookies(def usr-cookie (cookies/to-basic-client-cookie ["SRCHHPGUSR" { :discard false :domain ".bing.com", :path "/", :value "NRSLT=50" :expires (java.util.Date. 9000 1 1) }]))(cookies/add-cookie cs usr-cookie)(cookies/get-cookies cs);; => {"SRCHHPGUSR" {:discard false, :domain ".bing.com", :expires #inst "10900-01-31T16:00:00.000-00:00", :path "/", :secure false, :value "NRSLT=50", :version 0}}(def googles (search "google" { :max-page 3}))(count googles);; => 30 可以看到cookie并没有生效，在代理中也可以看到第一次请求时并没有带上添加的cookie。原因是HttpClient默认的Cookie specifications不会把.bing.com匹配到www.bing.com。
下面Api用法可以参考和:
(import org.apache.http.cookie.CookieOrigin)(import (org.apache.http.impl.cookie DefaultCookieSpec RFC6265LaxSpec RFC6265StrictSpec RFC2965Spec RFC2109Spec NetscapeDraftSpec IgnoreSpec BasicClientCookie2))(def bing-co (CookieOrigin. "www.bing.com" 80 "/" false))(def match-spec #(.match %1 usr-cookie bing-co))(def default-spec (DefaultCookieSpec.))(match-spec default-spec);; => false(def rfc6265-lax-spec (RFC6265LaxSpec.))(match-spec rfc6265-lax-spec);; => false(def rfc6265-strict-spec (RFC6265StrictSpec.))(match-spec rfc6265-strict-spec);; => false(def rfc2965-spec (RFC2965Spec.))(match-spec rfc2965-spec);; => true(def rfc2109-spec (RFC2109Spec.))(match-spec rfc2109-spec);; => true(def netscape-spec (NetscapeDraftSpec.))(match-spec netscape-spec);; => true;; 通过测试的几个spec,可以看到，默认只有rfc2*和netscape可以匹配.bing.com;; 下面设置cookie的attr(str usr-cookie);; => "[version: 0][name: SRCHHPGUSR][value: NRSLT=50][domain: .bing.com][path: /][expiry: Mon Feb 01 00:00:00 CST 10900]"(.setAttribute usr-cookie BasicClientCookie2/DOMAIN_ATTR "true")(str usr-cookie);; => "[version: 0][name: SRCHHPGUSR][value: NRSLT=50][domain: .bing.com][path: /][expiry: Mon Feb 01 00:00:00 CST 10900]";; 从表面上看不出设置了attr的区别，只有匹配时不同：(.getAttribute usr-cookie "domain") ; DOMAIN_ATTR的值是"domain";; => "true"(def match-spec #(.match %1 usr-cookie bing-co))(match-spec default-spec);; => true(match-spec rfc6265-lax-spec);; => true(match-spec rfc6265-strict-spec);; => true(match-spec rfc2965-spec);; => true(match-spec rfc2109-spec);; => true(match-spec netscape-spec);; => true;;再看搜索结果(cookies/clear-cookies cs)(cookies/add-cookie cs usr-cookie)(def googles (search "google" { :max-page 3}))(count googles);; => 78;; 不是每页都有50条,不过重要的是通过.setAttribute,cookie起作用了 具体原因是rfc6265的规定,参考
经过上面的测试，也可以在clj-http中使用netscape的cookie-policy来达到目的,因为standard属于rfc6265-lax,默认也不会匹配:
(def usr-cookie (cookies/to-basic-client-cookie ["SRCHHPGUSR" { :discard false :domain ".bing.com", :path "/", :value "NRSLT=50" :expires (java.util.Date. 9000 1 1) }]))(cookies/clear-cookies cs)(cookies/add-cookie cs usr-cookie)(def googles (search "google" { :max-page 3 :option { :cookie-policy :netscape}}))(count googles);; => 78 但是这种方法是不推荐的，还是用.setAttribute比较好。
Created: 2019-01-25 五 20:18