Group items tagged

you soon realise that every file and directory is uniquely addressable by its fully qualified path (either absolute or relative) and you can refer to each file and directory by its path. You are also aware that a valid path will uniquely resolve to only one directory or file.

the server allows you to retrieve the list of subdirectories and files within your current directory. It always shows you the current state of that directory.

following elements

A shared understanding of where the files will be uploaded, how they will be uniquely named, their specific file extensions (optionally) and the specific format of the file eg.

daemon process on the central office computer (the FTP server) which regularly scans the directory, parses each file as it comes it, does the relevant processing on it, and generates the appropriate result files and places them in the appropriate directories using the shared understanding of the directory structure and the file naming convention to communicate back the results of the processing.

RPC allowed you to invoke remote procedures by supporting an ability to pass messages which included the message name and the values for all the parameters necessary to be supplied to the message. Unlike FTP which was meant to do data transfer across a network, RPC was geared to do things remotely.

FTP required understanding of very few basic verbs (ls, cd, get, put). Thus the training required to understand FTP semantics was far less than that for RPC. This was partially due to the fact that RPC had a programmatic interface.

Moreover each time, new procedures were added or parameters added, these required programmatic changes

HTTP protoco

Unlike FTP and email, this required the authors to understand a new language, but used a simple markup syntax to keep the learning curve to the minimum

get/view/download/save a document

Along with RPC, these were essentially different technical manifestations of Service Oriented Architecture (SOA) principles.

Many services were usually expected to “do something” though quite often some services would simply return the requested data. Usually but not necessarily the services were identified by using ‘verbs’.

allow us to use the web to ‘do something’

Resource and media types as the basic units

Unique resource identifiers

Each resource has often one default manually readable representation

Each resource representation optionally includes contextually relevant hyperlinks to other resources

REST encourages a uniform interface

GET, PUT, POST and DELETE

Default Rendering

a default HTML rendering capability

Aspects such as non maintenance of conversational state, greatly increase the scalability of REST applications even if they do incur a minor cost in efficiency (which can be due to repeated redundant communication of data elements, or additional processing requirements due to preclusion of conversation state).

is much easier to understand from a data perspective than an invoice processor API.

However the simpler, cleaner and minimalistic abstractions often are far more important than feature richness. A point I would want to make in favour of REST even as I admit that conventional SOA technologies are far more feature rich than REST.

REST encourages you to view and model your architecture as a set of resources rather than services.