# 3.1  多功能的 Requests

* post

1.账号登录

2.搜索内容

3.上传图片

4.上传文件

5.往服务器传数据 等

* get

1.正常打开网页

2.不往服务器传数据

## requests get 请求

将parameters用字典代替, 然后传入 requests.get() 功能，用webbrowser模块打开一个默认浏览器, 观看在百度的搜索页面.

```python
import requests
import webbrowser
param = {"wd": "莫烦Python"}  # 搜索的信息
r = requests.get('http://www.baidu.com/s', params=param)
print(r.url)
webbrowser.open(r.url)

# http://www.baidu.com/s?wd=%E8%8E%AB%E7%83%A6Python
```

## requests post 请求

填入姓名的地方是在一个 < form> 里面

![](https://morvanzhou.github.io/static/results/scraping/3-1-8.png)

< form> 里面有一些 < input> 的tag, < input> 里面的 name="firstname"和 name="lastname"就是要post提交上去的关键信息

```python
data = {'firstname': '暴走', 'lastname': '林'}
r = requests.post('http://pythonscraping.com/files/processing.php', data=data)
print(r.text)

# Hello there, 暴走 林!
```

### 上传图片

传照片是 post 的一种

![](https://morvanzhou.github.io/static/results/scraping/3-1-10.png)

传送完照片以后的 url 有变动，“choose file” 按键链接的 < input> 是一个叫 uploadFile 的名字，将这个名字放入 python 的字典当一个 “key”

![](https://morvanzhou.github.io/static/results/scraping/3-1-11.png)

在字典中, 使用 open 打开一个图片文件, 当做要上传的文件，把这个字典放入 post 里面的 files 参数. 就能上传图片，网页会返回一个页面, 将图片名显示在上面.

```python
file = {'uploadFile': open('./image.png', 'rb')}
r = requests.post('http://pythonscraping.com/files/processing2.php', files=file)
print(r.text)

# The file image.png has been uploaded.
```

### 登录

![](https://morvanzhou.github.io/static/results/scraping/3-1-12.png)

![](https://morvanzhou.github.io/static/results/scraping/3-1-13.png)

登录账号, 浏览器做了:

1.使用 post 方法登录了第一个红框的 url

2.post 的时候, 使用了 Form data 中的用户名和密码

3.生成了一些 cookies

因为打开网页时, 每一个页面都是不连续的, 没有关联的, cookies 就是用来衔接一个页面和另一个页面的关系

用 requests.post + payload 的用户信息发给网页, 返回的 r 里面会有生成的 cookies 信息.

请求去登录后的页面时, 使用 request.get, 并将之前的 cookies 传入到 get 请求. 就能以登录的名义访问 get 的页面.

```python
payload = {'username': 'Morvan', 'password': 'password'}
r = requests.post('http://pythonscraping.com/pages/cookies/welcome.php', data=payload)
print(r.cookies.get_dict())

# {'username': 'Morvan', 'loggedin': '1'}


r = requests.get('http://pythonscraping.com/pages/cookies/profile.php', cookies=r.cookies)
print(r.text)

# Hey Morvan! Looks like you're still logged into the site!
```

![](https://morvanzhou.github.io/static/results/scraping/3-1-14.png)

### 使用 Session 登录

创建完一个 session 过后, 直接只用 session 来 post 和 get.

而且这次 get 的时候, 并没有传入 cookies. 但是实际上 session 内部

就已经有了之前的 cookies

```python
session = requests.Session()
payload = {'username': 'Morvan', 'password': 'password'}
r = session.post('http://pythonscraping.com/pages/cookies/welcome.php', data=payload)
print(r.cookies.get_dict())

# {'username': 'Morvan', 'loggedin': '1'}


r = session.get("http://pythonscraping.com/pages/cookies/profile.php")
print(r.text)

# Hey Morvan! Looks like you're still logged into the site!
```


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