Understanding Http, HttpRequest and HttpResponse.

- Http protocol always organized in sending Clients requests to the Server

- Key parts of the HttpRequest is:  Action client is asking server to take on behalf of the client.

- Every request has a request method contains action to take

- All requests applied to the specific resource on the server.  For example, accessing a webpage asking get request to get resource ../..*.html

- Request to find the resource in the server (eg: /app/mypage.html)

- Http Request methods -  Get, Post, Put and Delete

- Get is a simple request to the server can be without data or little data.  

- Post is typical used if you want to send lots of data to the server (for eg:  sending image to the server)

- Put is asking the server to store the data on the server.

- Delete is asking server to delete some resource.

- Format of the HttpRequest: <RequestMethod><Resource><Headers>(Extra information to help the server to assist with<ContentType><Cookie><RequestBody>

- How to find the client requesting the data from the server.  In server look for HttpRequest Header information.

- How to identify resource from client? - URL (Uniform Resource Locator) http://host:port/path

- Query parameters provides additional information required to filter the data. Eg:  URL?<Key><value>

- Multiple query parameters accepted by servers:  Eg:   URL?<key><value>&<key><value>

- URL encoding allows to pass a value that aren't allowed by replacing with the supported characters.

- Http Response Codes displays in the status line <ResponseCode><Text Description>

- Http Response contains Series of Headers to send Meta information to the clients.  Body of the response, which is actual data.

- Http Codes:  1xx - Information about the request, 2xxx - Successful request codes, 3xxx - Redirection(Resource moved in server and find in other location), 4xxx - Errors trigged by clients requested resource, 5xxx - Server errors