We all know that crawlers need proxy addresses to intervene. Using a proxy can hide your real IP address and prevent being blocked or restricted from accessing the website. Additionally, a proxy can help you bypass geo-restrictions and access blocked websites or services. However, please note that using a proxy may also bring some risks, such as the proxy server may record your access data, or the proxy server itself may have security holes. Therefore, when choosing a proxy, be sure to choose a trusted and secure proxy service provider.
When crawlers access target websites, they may face restrictions from anti-crawler mechanisms, such as IP restrictions, verification code restrictions, and so on. At this time, agents need to be used to solve these problems.
A proxy server is a computer located between a client and a target server, which can send requests to the target server instead of the client and return response data. Using a proxy can hide the client's real IP address, thereby circumventing restrictions on specific IP addresses or users. In addition, the use of proxies can also rotate IP, increase the success rate of access and prolong the survival period in the crawler process.
Specifically, the advantages of using a proxy are as follows:
Hide real IP
Using a proxy can hide your real IP and protect your privacy.
circumvent restrictions
Certain websites may be restricted based on IP addresses, and using a proxy can circumvent these restrictions by changing the IP address.
increase success rate
Using a proxy can increase the success rate and prevent the target website from being identified as junk traffic or abnormal traffic and being denied access.
prevent ban
Using a proxy can rotate IP, reduce the risk of being blocked by the target website, and increase the crawling survival cycle.
It should be noted that there are also some problems when using proxies or may lead to new anti-crawler mechanisms, such as poor proxy quality, excessively fast request frequency, proxy servers in too concentrated areas, etc. Therefore, when using a proxy, it is necessary to choose a high-quality proxy service provider, and reasonably adjust the request frequency and rotation proxy strategy according to the actual situation.
A detailed tutorial for reptiles using proxies
Using agents for crawler development can be achieved through the following steps:
Understand proxy types and working principles: Proxies are divided into two types: HTTP proxy and SOCKS proxy. HTTP proxy can only be used for HTTP protocol communication, while SOCKS proxy supports various application layer protocols (such as HTTP, FTP, SMTP, etc.). As an intermediary between the client and the target server, the proxy server will replace the client IP with the proxy server IP every time it requests, thereby hiding the real identity of the client.
Obtain proxy IP address: You can purchase high-quality commercial proxy services or use free public proxy API; you can also build a proxy server and use it yourself.
Set the proxy IP and port number: In Python, you can set the proxies parameter in the requests library to specify the proxy IP and port number. For example, using an HTTP proxy would look like this:
proxies = {
'http': 'http://127.0.0.1:8888', # 可以被替换成实际的代理 IP 和端口号
'https': 'https://127.0.0.1:8888'
}
response = requests.get(url, proxies=proxies)
Use random proxies: In order to avoid the anti-crawler game targeted at specific IPs by the target website, multiple proxy IPs can be used alternately in different requests. This can be achieved by using a proxy pool, etc.
proxies = get_random_proxy() # 随机获取可用的代理 IP
response = requests.get(url, proxies=proxies)
Monitor the running status of the agent: Since the agent is an intermediary and chained between multiple layers, various errors or exceptions may occur according to different systems or network environments. The agent can be tested and monitored during the development process, and the configuration can be adjusted or the agent can be switched in time for problems.
When using a proxy for crawler development, please pay attention to comply with relevant laws and regulations, and ensure the use of legal, stable and high-quality proxy services.