howtos » HTTP
This is a list of my “must-have” Mozilla Firefox add-ons. If you can recommend anything similar or better, be sure to drop me a comment.
Page Analysis & SEO
Minimise Nuisance
Bookmark Management
Download Management
Productivity
Web Development & Design
Security
Functional Extensions
Tab Management
Add-Ons Management
Page Analysis & SEO
About This Site Bookmarks - right-click on a page, select “About This Site Bookmarks” and you will see a list of handy links pointing off to informational sites such as Alexa, Compete, Netcraft, del.icio.us, etc.
Minimising Nuisance
Bookmark Management
Download Management
Download Statusbar - manage your downloads via the Firefox status bar.
DownThemAll - conveniently download all link targets on a page.
FlashGot - allows for single and multiple downloads utilising an external download manager of your choice (I prefer FlashGet).
Productivity
Auto Copy - highlight a piece of text and the selection is automatically copied to your clipboard.
FoxClocks - displays local times around the world in the statusbar or toolbar. Great for if you are dealing with friends and colleagues across multiple timezones.
FoxyTunes - operate your currently running media player from your Firefox statusbar.
Google Notebook - conveniently clip text and links to your Google Notebook.
Linkification - Converts text links (including e-mail addresses) into clickable links.
Web Development & Design
ColorZilla - eye-dropper tool that allows you to pick the HEX & RGB values of colours of elements on the page.
Firebug - the quintessential Javascript debugger. It also allows for excellent DOM and CSS debugging and manipulation.
IE View - open the current page in an IE window.
Live HTTP Headers - view HTTP request and response headers in realtime.
User Agent Switcher - allows you to spoof the User-Agent string and have Firefox masquerade as the Googlebot, etc, to see how your site reacts to different user-agents.
View Source Chart - renders page source HTML in an easy-to-read manner.
Web Developer - a must for the serious web developer.
YSlow - an addon to the Firebug debugger. It allows you to profile a page and identify bottlenecks. Provided by Yahoo. Also see Yahoo’s articles on improving page load performance.
Security
McAfee SiteAdvisor - lets you know if the currently viewed site is considered “safe” or not.
Functionality Extensions
CustomizeGoogle - customize your Google search and application experiences.
ErrorZilla - extends the standard page not found error screen with convenient links such as access to the page’s Google cached copy.
Tab Management
Faviconize Tab - minimize a tab’s width to the width of the favicon.
Add-Ons Management
FEBE - a convenient extensions & settings backup tool. Allows you to also run scheduled backups. The backups can be used to transport your extensions and their settings to another machine or Firefox profile.
MR Tech Local Install - install power tools for add-ons
The following is a list of HTTP Status Codes returned by a web server and what they mean. The information is summarised from RFC2616 Section 10.
Informational 1xx
Informational responses that contain no message bodies.
100 Continue - The client should continue with the request. Either the request is in a queue or the client should proceed with transmitting the rest of the request.
101 Switching Protocols - sent if the client requests a switch of protocols (e.g. from HTTP/1.0 to HTTP/1.1) and the server can comply.
Successful 2xx
Client’s request was successfully received, understood and accepted.
200 OK - The request was successful and here is the result of the request.
- GET -> entity corresponding to the requested resource
- POST -> entity describing or containing the result of the request
- HEAD -> entity-header fields for the requested resource (no message-body)
- TRACE -> an entity containing the request message as received by the end server
201 Created - A new resource has been created in response to the request. The URI of the new resource is contained in the Location header field. Additional URIs may be defined in the message-body.
202 Accepted - The request is in queue to be processed or is currently being processed. There is no way to find out later as to the status of your queued request. So the entity body should contain information such as: a URI to go to check status, estimated time of completion, number in queue, etc.
203 Non-Authorative Information - “The returned metainformation in the entity-header is not the definitive set as available from the origin server, but is gathered from a local or a third-party copy”
204 No Content - The server has fulfiled the request, but does not need to return a message-body. Meta information may be included in the entity header. If the client is a user agent, it should not change the current document view.
205 Reset Content - The server has fulfilled the request, and the user agent should reset the document view (e.g. clear all form field input values).
206 Partial Content - If the Range or If-Range header fields were used, the request returns partial content corresponding to the requested range.
Redirection 3xx
User agent needs to take further action to fulfil the request.
300 Multiple Choices - includes an entity containing a list of resource characteristics and locations from which the user-agent makes the appropriate selection. The entity format is determined by the value of the Content-Type header field.
301 Moved Permanently - indicates that the requested resource has been permanently moved to a new location. The new location should be included in a Location field.
302 Found - The requested resource resides temporarily at another location. The temporary location should be indicated in the Location field.
303 See Other - The response to the request can be found at another location and should be retrieved using a GET method. Used for a POST-activated script to redirect the user-agent to a status (or similar) page. New location should be indicated in the Location field.
304 Not Modified - in response to a conditional GET request. Must not contain a message-body.
305 Use Proxy - the requested resource must be accessed via the proxy indicated in the Location field.
307 Temporary Redirect - similar to the 302 code. Temporary location is indicated in the Location field.
Client Error 4xx
4xx errors indicate an error that occurred at the client’s end (eg. malformed URI, bad request, etc).
400 Bad Request - the request contained malformed syntax.
401 Unauthorized - request requires authorization. The client may repeat the request with a suitable Authorization header field. If an Authorization field was included, the 401 response indicates that the authorization failed.
403 Forbidden - the resource cannot be accessed even with authorization.
404 Not Found - the server could not find anything matching the request URI.
405 Method Not Allowed - the method specified in the Request-Line is not allowed for the requested resource.
406 Not Acceptable - the resource is only capable of generating response entities with a Content-Type that is different to what is indicated in the accept header fields.
407 Proxy Authentication Required - the client must authenticate itself with the proxy.
408 Request Timeout - client did not produce a request within the time that the server was prepared to wait.
409 Conflict - request could not be completed due to a conflict with the current state of the resource. For example, race conditions with a PUT request.
410 Gone - the resource is no longer located at the URI and a new location is not known.
411 Length Required - Content-Length field must be included.
412 Precondition Failed
413 Request Entity Too Large - request entity is larger than what the server is willing to handle.
414 Request-URI Too Long
415 Unsupported Media Type - entity of the request is in a format not supported by the requested resource for the resource method.
416 Requested Range Not Satisfiable
417 Expectation Failed - expectation in the Expect field could not be met.
Server Error 5xx
An error occurred on the server’s side.
500 Internal Server Error
501 Not Implemented - server does not recognise the request method OR cannot support the request method for the requested resource.
502 Bad Gateway - the server while acting as a proxy received an invalid response from an upstream server.
503 Service Unavailable - server is currently unable to handle the request. Length of the delay can be indicated in the Retry-After header field.
504 Gateway Timeout - the server while acting as a proxy did not receive a timely response from an upstream server.
505 HTTP Version Not Supported