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In Computer Networking a proxy server is a server application that acts as a intermediary for requests from clients seeking resources from servers that provide those resources.Instead of connecting directly to a server that can fulfill a requested resource, such as a file or web page for example, the client directs the request to the proxy server, which evaluates the request and performs the required network transactions. This serves as a method to simplify or control the complexity of the request, or provide additional benefits such as load balancing, privacy, or security. Proxies were devised to add structure and encapsulation to distributed systems
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Though a proxy server can be used to perform variety of operations like
- Improve Corporate and Institutional Security
- Carry Out Sensitive Tasks Anonymously
- Balance Traffic So Your Server Doesn’t Crash
- Control Employee Internet Usage
- Faster Speeds and Bandwidth Savings
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This project solely performs proxying for logging purposes and performing caching
- Caching is facility that is present inside a proxy server. Web proxy caching stores copies of frequently accessed Web objects (such as documents, images, and articles) close to users and serves this information to them. Internet users get their information faster, and Internet bandwidth is freed for other tasks.
- Internet users direct their requests to Web servers all over the Internet. For a caching server to serve these requests, it must act as a Web proxy server. A Web proxy server receives user requests for Web objects and either serves the requests or forwards them to the origin server (the Web server that contains the original copy of the requested information).
- Users enjoy a faster, more reliable experience by retrieving files that are already cached.
- Enterprises see higher customer satisfaction since proxies allow content to be delivered to customers faster.
- Enterprises also see lower administration costs since infrastructure can be outsourced to third parties such as CDNs.
- Caching reduces bandwidth consumption; therefore, it decreases network traffic and diminishes network congestion.
- Caching reduces access latency for two reasons:
- Frequently accessed documents are fetched from a nearby proxy cache instead of remote data servers; therefore, the transmission delay is minimized.
- Caching can reduce the network traffic, so those documents that are not cached can also be retrieved comparatively faster than without caching due to less congestion along the path and with less work load on the server.
- Caching reduces the workload of the remote web server by spreading the data widely among the proxy caches over the WAN.
- In a scenario where the remote server is not available due to a crash or network partitioning, the client can obtain a cached copy at the proxy. Hence, the robustness of the Web service is enhanced.
This project deals with setting up a proxy server along with the facility of caching. This project has been done on python and the core of proxy lies in the implementation of python sockets.
The projects involves certain functions which deals with the caching process.
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Cache_Memory():- This function acts as a memory for our caching process, it deals with keeping track of all the file resources that has been requested from the client. And for each request made we are saving certain details like the time at which the resource was requested and client address.
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Cache_Decision():- This function deals with deciding whether to cache current request or not. It checks for the number of times the resource has been requested. If it is more than the threshold then the file resource becomes eligible for second round of screening. In second phase it is tested whether the resource have been requested withing last 10 minutes or not. It it is, caching is done else not.
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Get_Current_Cache_Info():- This Functions deals with checking whether the resource have been already cached or not. And returns the cache path and the last modification time.
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freeup_cache():- If cache is full, then his functions deletes the cache record which has been not modified for a while.
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if_modified_since_header():- This function deals with modifying the request header, by adding an additional header in request named 'if-modified_since'. This header makes the request conditional. The server will send the request with 200 status, only if it has been modified after the given date. If the request has not been modified since, the response will be 304 without any body.
