R stands for RESOURCE. A resource could be a web page, an image, a domain object. URN = uniform resource name. URL = URN + descript of protocol to locate the resource (http://)
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CGI
Common Gateway Interface. Allowed web srvr 2 delegate requests for certain resources to another process. The process received the request details (HTTP request headers/body), the process prntln the resource content, captred by wb srvr & snt as rspse
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Probles with CGI
Poor security - subject to command injection flaws. C is infamous for being one of the least secure languages. Resource intensive (each request handled by entirely new process). No sharing of resources such as database connections.
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Servlets?
The Java equivalent of CGI.Java is a more secure language. Uses threads instead of processes. Much LIGHTER WEIGHT. Fast. Resources can be EASILY SHARED. Requires a Java Web Server (written in Java) eg - Apache Tomcat.
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Downside of Servlets
Printlning entire web pages is clunky. Would be much nicer if we could start with HTML and use placeholders for the dynamic content. This is what SSI is all about (Server Side Includes)
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Templating
An evolution of SSI. Puts the code that generates the dynamic content into the page itself. Adds a server-side scripting language to the HTML. Traditional templating = JSP (java server pages) Modern templates = handlebars.
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Templatingn
Improvement over the CGI/Servlet approach, but still messy. Handlebars is cleaner, but not self contained.
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Templating requires processing
Browsers dont understand JSP, PHP, Handlebars. Server side mechanism needs to process the template to produce final HTML. JSP files get converted into servelets.
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Model 2 Architecture.
Basically MVC for the web. Templating for the View and Servelts/CGI for the Controller. Templates for displaying content, CGI/Servlets for processing forms. eg Apache.
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Component Orientated
Applies desktop GUI framework concepts to web frameworks. Aims to completely separate HTML from application code. Application code creates GUI components - allows you to create reusable components.
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Event Driven
More about how the web server handles requests than how the content is created. The application and web server are basically the same thing. Eg Node JS. Web srvr fires an event when HTTP request arrives. Programmer can hook code to that event.
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Micro Frameworks
Event Driven. Often run on top of an event driven server such as Node.js. Do some basic processing of the request and response for you. Eg Jooby.
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Micro frameworks
Large collection of pluggable modules to add the additional features you need. Templating/session management/caching/security. Very flexible.
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Filter Chains
Common technique for adding features to web applications. HTTP request is passed through a chain of filters. Eech filter reads the request and performs actions. Allows frameowrks to have pluggable modules that operate on the requests/responses.
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Other cards in this set
Card 2
Front
CGI
Back
Common Gateway Interface. Allowed web srvr 2 delegate requests for certain resources to another process. The process received the request details (HTTP request headers/body), the process prntln the resource content, captred by wb srvr & snt as rspse
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