From 3ea12f7f8515d41bf2e52c0f56120e818160e119 Mon Sep 17 00:00:00 2001 From: xianhu Date: Tue, 1 Nov 2016 14:56:43 +0800 Subject: [PATCH] add python_requests.py --- README.md | 2 + python_requests.py | 216 +++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 218 insertions(+) create mode 100644 python_requests.py diff --git a/README.md b/README.md index 37900c5..af1c0ff 100644 --- a/README.md +++ b/README.md @@ -15,6 +15,8 @@ ### python_sqlalchemy.py: 作为一个Pythoner，不会SQLAlchemy都不好意思跟同行打招呼！ ### python_oneline.py: 几个小例子告诉你, 一行Python代码能干哪些事 + +### python_requests.py: Python中最好用的爬虫库Requests代码实例 ============================================================ ### 您可以fork该项目,并在修改后提交Pull request diff --git a/python_requests.py b/python_requests.py new file mode 100644 index 0000000..c6b905c --- /dev/null +++ b/python_requests.py @@ -0,0 +1,216 @@ +# _*_ coding: utf-8 _*_ + +""" +python_requests.py by xianhu +""" + +import requests + +# 尝试获取某个网页, 这里的r是一个Response对象 +r = requests.get("https://github.com/timeline.json") +print(type(r)) + +# Requests简便的API意味着所有HTTP请求类型都是显而易见的 +r1 = requests.post("http://httpbin.org/post") +r2 = requests.put("http://httpbin.org/put") +r3 = requests.delete("http://httpbin.org/delete") +r4 = requests.head("http://httpbin.org/get") +r5 = requests.options("http://httpbin.org/get") + +# 传递URL参数: 字典 +payload = {"key1": "value1", "key2": "value2"} +r = requests.get("http://httpbin.org/get", params=payload) +print(r.url) # http://httpbin.org/get?key2=value2&key1=value1 + +# 传递URL参数: 字典里带有列表 +payload = {"key1": "value1", "key2": ["value2", "value3"]} +r = requests.get("http://httpbin.org/get", params=payload) +print(r.url) # http://httpbin.org/get?key1=value1&key2=value2&key2=value3 + +# 获取正常内容 +r = requests.get("https://github.com/timeline.json") +print(r.text) # "[{"repository":{"open_issues":0,"url":"https://github.com/... +print(r.encoding) # "utf-8" + +# Requests会自动解码来自服务器的内容(基于HTTP头部对响应的编码作出有根据的推测), 或者你自己更改 +r.encoding = "ISO-8859-1" +print(r.text) # 此时使用新的r.encoding新值 + +# 二进制响应内容, Requests会自动为你解码 gzip 和 deflate 传输编码的响应数据 +print(r.content) # b"[{"repository":{"open_issues":0,"url":"https://github.com/... + +# JSON 响应内容, Requests中也有一个内置的JSON解码器 +print(r.json()) # [{u"repository": {u"open_issues": 0, u"url": "https://github.com/... + +# 原始响应内容: 获取来自服务器的原始套接字响应 +r = requests.get("https://github.com/timeline.json", stream=True) +print(r.raw) # +print(r.raw.read(10)) # "\x1f\x8b\x08\x00\x00\x00\x00\x00\x00\x03" + +# 但一般情况下, 应该以下面的模式将文本流保存到文件 +with open("test", "wb") as fd: + for chunk in r.iter_content(chunk_size=256): + fd.write(chunk) + +# 定制请求头: 一个字典 +headers = {"user-agent": "my-app/0.0.1"} +r = requests.get("https://api.github.com/some/endpoint", headers=headers) +print(r.request.headers) # 获取该请求的头部 + +# 更加复杂的POST请求: 表单 +payload = {"key1": "value1", "key2": "value2"} +r = requests.post("http://httpbin.org/post", data=payload) +print(r.text) + +# POST一个多部分编码(Multipart-Encoded)的文件 +files = {"file": open("report.xls", "rb")} +r = requests.post("http://httpbin.org/post", files=files) +print(r.text) + +# 你可以显式地设置文件名, 文件类型和请求头 +files = {"file": ("report.xls", open("report.xls", "rb"), "application/vnd.ms-excel", {"Expires": "0"})} +r = requests.post("http://httpbin.org/post", files=files) +print(r.text) + +# 你也可以发送作为文件来接收的字符串 +files = {"file": ("report.csv", "some,data,to,send\nanother,row,to,send\n")} +r = requests.post("http://httpbin.org/post", files=files) +print(r.text) + +# 响应状态码 +r = requests.get("http://httpbin.org/get") +print(r.status_code) # 200 +print(r.status_code == requests.codes.ok) # True 响应状态码查询 + +# 如果发送了一个错误请求(4XX客户端错误, 或5XX服务器错误响应), 可以通过 Response.raise_for_status() 来抛出异常: +bad_r = requests.get("http://httpbin.org/status/404") +print(bad_r.status_code) # 404 +bad_r.raise_for_status() +# Traceback (most recent call last): +# File "requests/models.py", line 832, in raise_for_status +# raise http_error +# requests.exceptions.HTTPError: 404 Client Error + +# 响应头, 一个Python字典形式展示的服务器响应头, HTTP头部是大小写不敏感的 +print(r.headers) +# { +# "content-encoding": "gzip", +# "transfer-encoding": "chunked", +# "connection": "close", +# "server": "nginx/1.0.4", +# "x-runtime": "148ms", +# "etag": "e1ca502697e5c9317743dc078f67693f", +# "content-type": "application/json" +# } +print(r.headers["Content-Type"]) # "application/json" +print(r.headers.get("content-type")) # "application/json" + +# Cookie: 如果某个响应中包含一些 cookie +r = requests.get("http://example.com/some/cookie/setting/url") +print(r.cookies["example_cookie_name"]) # "example_cookie_value" + +# 要想发送你的cookies到服务器, 可以使用cookies参数, 一个字典 +cookies = dict(cookies_are="working") +r = requests.get("http://httpbin.org/cookies", cookies=cookies) +print(r.text) + +# 会话对象: 会话对象让你能够跨请求保持某些参数, 它也会在同一个 Session 实例发出的所有请求之间保持cookie +s = requests.Session() +s.get("http://httpbin.org/cookies/set/sessioncookie/123456789") +r = s.get("http://httpbin.org/cookies") +print(r.text) # '{"cookies": {"sessioncookie": "123456789"}}' + +# 会话也可用来为请求方法提供缺省数据, 这是通过为会话对象的属性提供数据来实现的 +s = requests.Session() +s.auth = ("user", "pass") +s.headers.update({"x-test": "true"}) +s.get("http://httpbin.org/headers", headers={"x-test2": "true"}) # both "x-test" and "x-test2" are sent + +# 不过需要注意, 就算使用了会话, 方法级别的参数也不会被跨请求保持 +# 下面的例子只会和第一个请求发送cookie, 而非第二个 +s = requests.Session() +r = s.get("http://httpbin.org/cookies", cookies={"from-my": "browser"}) +print(r.text) # '{"cookies": {"from-my": "browser"}}' +r = s.get("http://httpbin.org/cookies") +print(r.text) # '{"cookies": {}}' +# 如果你要手动为会话添加 cookie, 就是用 Cookie utility 函数来操纵Session.cookies + +# 会话还可以用作前后文管理器 +with requests.Session() as s: + s.get("http://httpbin.org/cookies/set/sessioncookie/123456789") + +# 重定向与请求历史, 默认情况下, 除了HEAD, Requests会自动处理所有重定向 +# 可以使用响应对象的history方法来追踪重定向 +# Response.history 是一个 Response 对象的列表, 为了完成请求而创建了这些对象. 这个对象列表按照从最老到最近的请求进行排序 +r = requests.get("http://github.com") +print(r.status_code) # 200 +print(r.history) # [] + +# 如果你使用的是GET、OPTIONS、POST、PUT、PATCH 或者 DELETE, 那么你可以通过 allow_redirects 参数禁用重定向处理 +r = requests.get("http://github.com", allow_redirects=False) +print(r.status_code) # 301 +print(r.history) # [] + +# 如果你使用了HEAD, 你也可以启用重定向 +r = requests.head("http://github.com", allow_redirects=True) +print(r.history) # [] + +# 超时, 设置timeout参数 +requests.get("http://github.com", timeout=0.001) +# Traceback (most recent call last): +# File "", line 1, in +# requests.exceptions.Timeout: HTTPConnectionPool(host="github.com", port=80): Request timed out. (timeout=0.001) + +# 注意: timeout仅对连接过程有效, 与响应体的下载无关 +# timeout并不是整个下载响应的时间限制, 而是如果服务器在timeout秒内没有应答, 将会引发一个异常 +# 更精确地说, 是在 timeout 秒内没有从基础套接字上接收到任何字节的数据时 +requests.get("https://github.com", timeout=5) +# 这一 timeout 值将会用作 connect 和 read 二者的 timeout +# 如果要分别制定, 就传入一个元组 +requests.get("https://github.com", timeout=(3.05, 27)) + +# 错误与异常: 遇到网络问题(如: DNS 查询失败、拒绝连接等)时, Requests 会抛出一个 ConnectionError 异常 +# 如果 HTTP 请求返回了不成功的状态码, Response.raise_for_status() 会抛出一个 HTTPError 异常 +# 若请求超时, 则抛出一个 Timeout 异常 +# 若请求超过了设定的最大重定向次数, 则会抛出一个 TooManyRedirects 异常 +# 所有Requests显式抛出的异常都继承自 requests.exceptions.RequestException + +# SSL证书验证, verify设置为True表示检查证书, 设置为False表示忽略证书 +requests.get("https://kennethreitz.com", verify=True) # 未设置SSL证书, 抛出异常 +# requests.exceptions.SSLError: hostname "kennethreitz.com" doesn"t match either of "*.herokuapp.com", "herokuapp.com" +requests.get("https://github.com", verify=True) # , 已设置SSL证书 +# 对于私有证书，你也可以传递一个 CA_BUNDLE 文件的路径给 verify + +# 你也可以指定一个本地证书用作客户端证书, 可以是单个文件（包含密钥和证书）或一个包含两个文件路径的元组: +requests.get("https://kennethreitz.com", cert=("/path/server.crt", "/path/key")) +requests.get("https://kennethreitz.com", cert="/wrong_path/server.pem") +# SSLError: [Errno 336265225] _ssl.c:347: error:140B0009:SSL routines:SSL_CTX_use_PrivateKey_file:PEM lib +# 警告: 本地证书的私有 key 必须是解密状态. 目前Requests不支持使用加密的 key + +# 流式上传, 允许你发送大的数据流或文件而无需先把它们读入内存 +with open("massive-body") as f: + requests.post("http://some.url/streamed", data=f) + + +# 事件挂钩, 可用的钩子: response(从一个请求产生的响应) +# 你可以通过传递一个 {hook_name: callback_function} 字典给 hooks 请求参数为每个请求分配一个钩子函数 +def print_url(resp): + print(resp.url) + return +requests.get("http://httpbin.org", hooks=dict(response=print_url)) + +# 代理 +proxies = { + "http": "http://10.10.1.10:3128", + "https": "http://10.10.1.10:1080", +} +requests.get("http://example.org", proxies=proxies) +# 若代理需要使用HTTP Basic Auth, 可以使用http://user:password@host:port/, 比如"http": "http://user:pass@10.10.1.10:3128/" + +# 除了基本的 HTTP 代理, Request 还支持 SOCKS 协议的代理 +# $ pip install requests[socks] +proxies = { + "http": "socks5://user:pass@host:port", + "https": "socks5://user:pass@host:port" +} +requests.get("http://example.org", proxies=proxies)