Mobility Information Series

Transcription

1 SOAP vs REST RapidValue Enabling Mobility XML vs JSON Mobility Information Series Comparison between various Web Services Data Transfer Frameworks for Mobile Enabling Applications Author: Arun Chandran, Technical Architect, RapidValue Solutions

2 Contents Introduction SOAP vs. REST Performance Maintenance Security Transactions Messaging Additional Parameters XML vs. JSON Performance Scenario Timing CPU/Memory Summary About RapidValue Mobility Information Series Jan 201

3 Introduction This document is a guide for developers and architects to select an appropriate framework to transfer data between server and mobile devices. It explains the difference between two popular web services architecture - SOAP & REST, and compares performance, maintenance, security, transactions, messaging etc. between the two frameworks. The document also examines the pros and cons of two commonly used data-interchange formats i.e. XML and JSON. Ideal Approaches for Mobile Devices There are two commonly used web services architecture - SOAP and REST. SOAP (Simple Object Access Protocol) and REST (Representational State Transfer) provide mechanisms for requesting information from endpoints (SOAP) or from resources (REST). SOAP has a more formal definition mechanism called WSDL (Web Services Definition Language) and is slightly more complex to implement than REST. REST uses the standard HTTP request and response mechanism, simplifies implementation and provides a looser coupling of client and server. REST has several advantages over SOAP. It is light weight. Therefore, data being passed will be lesser over the network (since data is passed over a network to a mobile device). This makes a considerable difference especially when Internet speed is low. SOAP vs. REST The table below provides a brief comparison between SOAP and REST. # SOAP REST 1 A XML-based message protocol An architectural style protocol Uses WSDL for communication between consumer and provider Invokes services by calling RPC method Does not return human readable result Transfer is over HTTP. Also uses other protocols such as SMTP, FTP, etc. JavaScript can call SOAP, but it is difficult to implement Performance is not great compared to REST Uses XML or JSON to send and receive data Simply calls services via URL path Result is readable which is just plain XML or JSON Transfer is over HTTP only Easy to call from JavaScript Performance is much better compared to SOAP - less CPU intensive, leaner code etc. Mobility Information Series Jan 201 0

4 This section describes differences between SOAP and REST in more detail: Performance REST is easier to use in JavaScript code as you can simply pass the data packet directly into a JavaScript array without any parsing, extracting and converting lesser CPU intensive, since the CPU s of mobile/tablets might be of lesser capacity compared to a laptop/desktop. If the load of the server is considered, REST has slightly better performance since it accepts minimal overhead on top of HTTP. Usually SOAP brings with it a stack of different handlers and parsers. However, the performance difference by itself is not that large, but RESTful service is easier to scale up since there are no server side sessions. If the performance of the network i.e. bandwidth is considered, REST has better performance, since it is only HTTP and no overhead. Therefore, if the service runs on top of HTTP, it cannot get much leaner than REST. Furthermore, if you encode your representations in JSON (as opposed to XML), you will save many more bytes. REST reads can be cached, SOAP based reads cannot be cached. In general, REST has better performance and scalability. Maintenance Building clients, developing APIs, and understanding the technical documentation is easier with REST than with SOAP. Security SOAP supports SSL and WS-Security which includes enterprise security features. It provides identity through intermediaries, not just point-to-point (SSL). It also provides standard implementation of data integrity and data privacy. It supports some security tools that typical internet services do not require; in fact they are mostly needed in few enterprise scenarios. Transactions REST is limited to HTTP which cannot provide two-phase commit across distributed transactional resources, whereas SOAP is capable. Mobility Information Series Jan 201 0

5 Messaging REST does not have a standard messaging system and expects clients to deal with communication failures by retrying. SOAP has successful/retry logic built-in and provides end-to-end reliability even through SOAP intermediaries. Additional Parameters Most mobile SDKs and jquery support REST REST supports synchronous and asynchronous process for mobiles REST makes interface utilization easier in the client (device). Therefore, not only your server becomes leaner but the client too. XML vs. JSON 1 There are various formats available to transfer data between client and server. The most commonly used ones are JSON and XML. Extensible Markup Language (XML) is a markup language that defines a set of rules for encoding documents in a format which is both human-readable and machine-readable. JavaScript Object Notation (JSON) is a text-based open standard designed for human-readable data interchange. It is derived from the JavaScript scripting language for representing simple data structures and associative arrays called objects. In spite of its relationship to JavaScript, it is languageindependent with parsers available for many languages. JSON format is often used for serializing and transmitting structured data over a network connection. It is used primarily to transmit data between a server and web application. It serves as an alternative to XML. The table below provides a brief comparison between XML and JSON: # XML JSON XSD Validation Includes namespaces Requires parsing. xml doc is parsed through parameters like xpath etc. JavaScript work with strings. May require additional parsing Write JavaScript to parse the xml objects Heavy compared to JSON No Validation No namespaces Parsing is just an eval. Therefore it is fast. In JavaScript, we can work with objects-run time evaluation of types A JavaScript object JSON is light weight compared to XML Mobility Information Series Jan

6 Performance This section explains the difference between JSON and XML in the form of an experiment. This section consists of test case results from a case study - research conduced by department of Computer Science, Montana State University Bozeman, USA. These test cases are designed and implemented to compare transmission times and resource utilizations of JSON and XML.The results illustrate the differences between JSON and XML encoding under varying transmission scenario. Scenario 2 : A time-consuming transmission of large number of objects. Large numbers of objects are used in order to achieve accurate average measurements. The client sends one million encoded objects to the server for both JSON and XML. The results are as follows: Timing Parameters Number of Objects Total time to transfer million objects (ms) Average time (ms) JSON 1 million XML 1 million CPU/Memory Format Average % User CPU Utilization Average % System CPU Utilization Average % Memory Utilization JSON XML Source: 1 Wikipedia definitions 2 Comparison of JSON and XML Data Interchange Formats: A Case Study by Nurzhan Nurseitov, Michael Paulson, Randall Reynolds, Clemente Izurieta, Montana State University Mobility Information Series Jan 201 0

7 Summary Based on our experience and usage of various web service frameworks, our recommendations are as follows: If the application requires transferring highly secure data, then the best option will be to use SOAP. If high security is not a concern, then REST would be the ideal choice as REST services is easier to develop, maintain and performance of the application will be better - consumes lesser CPU memory, works well at lower bandwidth even during high transactions. JSON is recommended over XML for data transmission over the Internet, especially when interactions with mobile devices are involved since it is light weight data-interchange format. If you have any questions or need further information, please do write to us. Mobility Information Series Jan

8 About RapidValue RapidValue is a leading provider of end-to-end mobility solutions to enterprises worldwide. Armed with a large team of experts in mobility consulting and application development, along with experience delivering global mobility projects, we offer a range of mobility services across industry verticals. RapidValue delivers its services to the world s top brands and Fortune 1000 companies, and has offices in the United States and India contactus@rapidvaluesolutions.com Mobility Information Series Jan 201