Compare and contrast REST and SOAP web services

Question

I currently figure out the similar is both using internet protocol  HTTP  to exchange data between consumer and provider    The difference is    SOAP is a XML-based message protocol  while REST is an architectural style SOAP uses WSDL for communication between consumer and provider  whereas REST just uses XML or JSON to send and receive data SOAP invokes services by calling RPC method  REST just simply calls services via URL path SOAP doesn t return human readable result  whilst REST result is readable with is just plain XML or JSON SOAP is not just over HTTP  it also uses other protocols such as SMTP  FTP  etc  REST is over only HTTP   That s everything I know as the differences between them  Could anyone correct me and add more

User · Accepted Answer

SOAP uses WSDL for communication btw consumer and provider, whereas REST just uses XML or JSON to send and receive data

WSDL defines contract between client and service and is static by its nature. In case of REST contract is somewhat complicated and is defined by HTTP, URI, Media Formats and Application Specific Coordination Protocol. It's highly dynamic unlike WSDL.

SOAP doesn't return human readable result, whilst REST result is readable with is just plain XML or JSON

This is not true. Plain XML or JSON are not RESTful at all. None of them define any controls(i.e. links and link relations, method information, encoding information etc...) which is against REST as far as messages must be self contained and coordinate interaction between agent/client and service.

With links + semantic link relations clients should be able to determine what is next interaction step and follow these links and continue communication with service.

It is not necessary that messages be human readable, it's possible to use cryptic format and build perfectly valid REST applications. It doesn't matter whether message is human readable or not.

Thus, plain XML(application/xml) or JSON(application/json) are not sufficient formats for building REST applications. It's always reasonable to use subset of these generic media types which have strong semantic meaning and offer enough control information(links etc...) to coordinate interactions between client and server.

For more details regarding control information I highly recommend to read this: http://www.amundsen.com/hypermedia/hfactor/
Web Linking: http://tools.ietf.org/html/rfc5988
Registered link relations: http://www.iana.org/assignments/link-relations/link-relations.xml

REST is over only HTTP

Not true, HTTP is most widely used and when we talk about REST web services we just assume HTTP. HTTP defines interface with it's methods(GET, POST, PUT, DELETE, PATCH etc) and various headers which can be used uniformly for interacting with resources. This uniformity can be achieved with other protocols as well.

P.S. Very simple, yet very interesting explanation of REST: http://www.looah.com/source/view/2284

User · Answer

In day to day  practical programming terms  the biggest difference is in the fact that with SOAP you are working with static and strongly defined data exchange formats where as with REST and JSON data exchange formatting is very loose by comparison  For example with SOAP you can validate that exchanged data matches an XSD schema  The XSD therefore serves as a  contract  on how the client and the server are to understand how the data being exchanged must be structured   JSON data is typically not passed around according to a strongly defined format  unless you re using a framework that supports it    e g  http   msdn microsoft com en-us library jj870778 aspx or implementing json-schema    In-fact  some  many most  would argue that the  dynamic  secret sauce of JSON goes against the philosophy culture of constraining it by data contracts  Should JSON RESTful web services use data contract   People used to working in dynamic loosely typed languages tend to feel more comfortable with the looseness of JSON while developers from strongly typed languages prefer XML   http   www mnot net blog 2012 04 13 json or xml just decide

User · Answer

SOAP brings it   s own protocol and focuses on exposing pieces of application logic  not data  as services  SOAP exposes operations  SOAP is focused on accessing named operations  each implement some business logic through different interfaces   Though SOAP is commonly referred to as    web services    this is a misnomer  SOAP has very little if anything to do with the Web  REST provides true    Web services    based on URIs and HTTP   By way of illustration here are few calls and their appropriate home with commentary   getUser User     This is a rest operation as you are accessing a resource  data    switchCategory User  OldCategory  NewCategory    REST permits many different data formats where as SOAP only permits XML  While this may seem like it adds complexity to REST because you need to handle multiple formats  in my experience it has actually been quite beneficial  JSON usually is a better fit for data and parses much faster  REST allows better support for browser clients due to it   s support for JSON

[web-services] Compare and contrast REST and SOAP web services?

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