Apache HttpComponents中的cookie匹配策略
1 简介
在clojure中使用clj-http抓取网页时，须要提交自定义cookie,老是不能成功发送，研究一下HttpClient中Cookie的工做方式。 css
clj-http包装了HttpClient库，对于请求页面时发回的状态能够自动处理，可是须要本身往请求中添加cookie时老是失败，折腾了好久，了解了HttpClient处理Cookie的细节，关于HttpClient中HTTP的状态管理，能够参考HttpClient的官方指南 html
2 示例
从bing获取搜索结果，代码以下： java
deps.edn文件以下: python
{ :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： sql
(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 请收藏咱们的网址"}
能够看到一页返回10个结果，若是要返回50(bing设置里最大结果数量)，则要设置cookie项： "SRCHHPGUSR" 的值为： "NRSLT=50" shell
下面添加cookie： apache
(cookies/clear-cookies cs) ;清除以前请求产生的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
能够看到cookie并无生效，在代理中也能够看到第一次请求时并无带上添加的cookie。缘由是HttpClient默认的Cookie specifications不会把.bing.com匹配到www.bing.com。 api
下面Api用法能够参考CookieOrigin API文档和cookie package文档: sass
(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 ;; 经过测试的几个spec,能够看到，默认只有rfc2*和netscape能够匹配.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，只有匹配时不一样： (.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,不太重要的是经过.setAttribute,cookie起做用了
具体缘由是rfc6265的规定,参考overflow的回答 ruby
通过上面的测试，也能够在clj-http中使用netscape的cookie-policy来达到目的,由于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
可是这种方法是不推荐的，仍是用.setAttribute比较好。