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HTTP is an application layer protocol in the Internet protocol suite model for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide Web, where hypertext documents include hyperlinks to other resources that the user can easily access, for example by a mouse click or by tapping the screen in a web browser.
The Session Initiation Protocol (SIP) is a signaling protocol used for initiating, maintaining, and terminating communication sessions that include voice, video and messaging applications. SIP is used in Internet telephony, in private IP telephone systems, as well as mobile phone calling over LTE (VoLTE).
A web server is computer software and underlying hardware that accepts requests via HTTP or its secure variant HTTPS. A user agent, commonly a web browser or web crawler, initiates communication by making a request for a web page or other resource using HTTP, and the server responds with the content of that resource or an error message. A web server can also accept and store resources sent from the user agent if configured to do so.
In computer network communications, the HTTP 404, 404 not found, 404, 404 error, page not found, or file not found error message is a hypertext transfer protocol (HTTP) standard response code, to indicate that the browser was able to communicate with a given server, but the server could not find what was requested. The error may also be used when a server does not wish to disclose whether it has the requested information.
URL redirection, also called URL forwarding, is a World Wide Web technique for making a web page available under more than one URL address. When a web browser attempts to open a URL that has been redirected, a page with a different URL is opened. Similarly, domain redirection or domain forwarding is when all pages in a URL domain are redirected to a different domain, as when wikipedia.com and wikipedia.net are automatically redirected to wikipedia.org.
A query string is a part of a uniform resource locator (URL) that assigns values to specified parameters. A query string commonly includes fields added to a base URL by a Web browser or other client application, for example as part of an HTML document, choosing the appearance of a page, or jumping to positions in multimedia content.
XMLHttpRequest (XHR) is an API in the form of a JavaScript object whose methods transmit HTTP requests from a web browser to a web server. The methods allow a browser-based application to make a fine-grained server call and store the results in XMLHttpRequest's responseText attribute. XMLHttpRequest is a component of Ajax programming. Prior to Ajax, hyperlinks and form submissions were the primary mechanisms for interacting with the server, often replacing the current page with another one.
Content negotiation refers to mechanisms defined as a part of HTTP that make it possible to serve different versions of a document at the same URI, so that user agents can specify which version fits their capabilities the best. One classical use of this mechanism is to serve an image in GIF or PNG format, so that a browser that cannot display PNG images will be served the GIF version.
In HTTP, "Referer" is an optional HTTP header field that identifies the address of the web page, from which the resource has been requested. By checking the referrer, the server providing the new web page can see where the request originated.
Callback verification, also known as callout verification or Sender Address Verification, is a technique used by SMTP software in order to validate e-mail addresses. The most common target of verification is the sender address from the message envelope. It is mostly used as an anti-spam measure.
HTTPS 403 is an HTTP status code meaning access to the requested resource is forbidden. The server understood the request, but will not fulfill it, if it was correct.
The HTTP response status code 302 Found is a common way of performing URL redirection. The HTTP/1.0 specification initially defined this code, and gave it the description phrase "Moved Temporarily" rather than "Found".
The HTTP response status code 303 See Other is a way to redirect web applications to a new URI, particularly after a HTTP POST has been performed, since RFC 2616.
HTTP Status Code 402, also known as "Payment Required," is a standard response code in the Hypertext Transfer Protocol (HTTP). It is part of the HTTP/1.1 protocol defined by the Internet Engineering Task Force (IETF) in the RFC 7231 specification.
In computing, POST is a request method supported by HTTP used by the World Wide Web. By design, the POST request method requests that a web server accepts the data enclosed in the body of the request message, most likely for storing it. It is often used when uploading a file or when submitting a completed web form.
WebSocket is a computer communications protocol, providing a simultaneous two-way communication channel over a single Transmission Control Protocol (TCP) connection. The WebSocket protocol was standardized by the IETF as RFC 6455 in 2011. The current specification allowing web applications to use this protocol is known as WebSockets. It is a living standard maintained by the WHATWG and a successor to The WebSocket API from the W3C.
Cross-origin resource sharing (CORS) is a mechanism that allows a web page to access restricted resources from a server on a domain different than the domain that served the web page.
References
- ↑ developer.mozilla.org 502 Bad Gateway
- ↑ RFC7231.txt
- ↑ Fielding; et al. (June 1999). 6.6.3 502 Bad Gateway. IETF. p. 63. sec. 6.6.3. doi: 10.17487/RFC7231 . RFC 7231.
- ↑ How do I solve the problem with the 502 Bad Gateway status code?