- Spdy's development goals are designed to address HTTP performance bottlenecks and shorten the load time of Web pages.
- The bottleneck of HTTP
- Only one request can be sent on a connection.
- Requests can only be started from the client. The client is not allowed to receive directives other than the response.
- The request/response is sent without compression. The more the header information, the greater the delay.
- Send a lengthy header. It is wasteful to send the same header each time.
- You can choose any data compression format. Non-forced compression is sent.
- Ajax is an efficient use of JavaScript and DOM operations to achieve partial Web page replacement loading of asynchronous communication means. (Asynchronous loading)
- Comet, once the server side has content updates, comet will not let the request wait, but directly to the client to return the response. This is a function of simulating server-to-client push through delayed response.
- The spdy is not completely rewritten as an HTTP protocol, but is operated in the form of a new session layer between the application layer of TCP/IP and transport. At the same time, Spdy specifies that SSL is used in communications, given the security implications.
- After using Spdy, the HTTP protocol has the following additional features.
- Multiplexing streams, which allow unlimited processing of multiple HTTP requests through a single TCP link.
- Given the request priority, Spdy not only can handle requests indefinitely, but can also assign priority order to requests individually.
- Compresses the HTTP header, compressing the HTTP request and the response header.
- Push feature that supports the ability of the server to proactively push data to the client.
- Server prompting feature, the server can proactively prompt the client to request the required resources.
- Websocket,web the full-duplex communication standard between the browser and the Web server.
- Push feature that enables push of data pushed by the server to the client.
- Reduce traffic, as long as the WebSocket connection is established, you want to keep the connection status
- Handshake request, in order to achieve websocket communication, need to use the HTTP Upgrade header field, to inform the server communication protocol changes to achieve the purpose of handshake.
- The handshake response, for the previous request, returns the response of the status Code 101 switching protocols.
- Http/2.0, the goal is to improve the user's speed experience when using the Web.
- SPDY
- HTTP speed + Mobility
- network-friendly HTTP Upgrade
- WebDAV is a distributed file system that allows you to copy, edit, and more directly on the contents of a Web server.
- Concept
- Collection, is a unified management of the concept of multiple resources, in a collection of units can do a variety of operations. You can also implement a collection of similar collections such as overlays.
- Resources, which refer to files or collections as resources.
- Property that defines the properties of the resource. The definition is executed in the format "name = value".
- Lock and set the file to a state that cannot be edited. When multiple people are editing at the same time, you can prevent content writing at the same moment.
- New method
- PROPFIND, getting properties
- PROPPATCH, modifying properties
- MKCOL, creating a collection
- Copy, copying resources and attributes
- Move, moving Resources
- Lock, Resource plus lock
- UNLOCK, Unlocking resources
- Status code
- 102 Processing: Requests are handled normally but are currently in process state
- 207 Multi-Status: There are multiple states
- 422 unprocessible Entity: Correct format, incorrect content
- 423 Locked: The resource has been locked
- 424 Failed Dependency: Processing a request associated with a request failed, so dependency is no longer maintained
- 507 Insufficient Storage: Insufficient space to save
HTTP Knowledge Popularization series: HTTP-based feature append protocol