Introduction to RESTful Web Services. Presented by Steve Ives

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1 1 Introduction to RESTful Web Services Presented by Steve Ives

2 Introduction to RESTful Web Services What are web services? How are web services implemented? Why are web services used? Categories of web services History of.net web service technologies RESTful web services the state of the art OData services taking things to the next level Importance to your business? Focus during this conference Teaser Harmony Core 2

3 3 What are Web Services?

4 What are Web Services? Software systems designed to support interoperable machine-tomachine interaction over a network. (W3C) Web services expose Data Business logic Via the web Remote procedure calls via standard tools Called by client software Desktop or server apps Websites Other web services Mobile apps Internet of Things Published APIs Great alternative to custom components Standard protocols and payloads Zero client footprint 4

5 5 How Are Web Services Implemented?

6 How Are Web Services Implemented? Web services are cross-platform languageindependent remote function calls. WEB SERVICE = CODE + NETWORK PROTOCOL + DATA FORMAT 6

7 Web Service Code Web services contain operations that perform various actions. Operations are methods web services are remotely callable functions. The clever part is the network messaging, serialization of data, etc. The easy part is writing the code! 7

Internet friendly Firewall friendly Occasionally other protocols

8 Web Service Network Protocols HTTP or HTTPS Simple and effective protocol Widely supported across platforms & development environments Internet friendly Firewall friendly Occasionally other protocols within private LAN WCF socket endpoints, etc. Specific one-to-one scenarios 8

Web Service Data Interchange Formats Simple

characters Notation Protocol (JSON) (SOAP) 401

9 Web Service Data Interchange Formats Simple Plain JavaScript XML Object Object 556 Access characters Notation Protocol (JSON) (SOAP) characters Most web services now use JSON. Some continue to offer XML alternative. Most frameworks serialize & deserialize data automatically. 9

10 10 Why Are Web Services Used?

11 Why Are Web Services Used? Achieve interoperability between systems & applications Combine best aspects of component-based development & web Platform & language agnostic Decoupled Clients don t know or care how services are implemented. Services don t know or care how clients are implemented. Follow the rules and it just works! Scalable (if well designed) Multiple deployment options Great ROI Expose functionality once. Call it from multiple client apps. 11

12 12 Categories of Web Services

13 Public API Common use cases Public information or service Selling information or service App store mobile apps Published desktop apps Audience Open to anyone Often requires registration May require fees Connectivity Internet API Usually designed for widespread use Internet Web service Application & data servers Various & unknown consumers 13

Restricted Use API Common use cases B2B, interaction

Limited, known, authorized Connectivity Internet API

Customer or vendor application server Internet Web

14 Restricted Use API Common use cases B2B, interaction with partner entities Supporting a mobile app Audience Limited, known, authorized Connectivity Internet API Typically designed for a single specific consumer/app Customer or vendor application server Internet Web service Company mobile app (external use) Application & data servers 14

Private API Common use cases Corporate web sites Systems integration

Connectivity Internet or private network API Sometimes specific to a

Corporate web server In-house remote application Web service Internet ESB

15 Private API Common use cases Corporate web sites Systems integration Internal use mobile apps Audience Restricted, internal, controlled Connectivity Internet or private network API Sometimes specific to a single use case Sometimes general purpose Enterprise Service Bus (ESB) Corporate web server In-house remote application Web service Internet ESB Application & data servers Company mobile app (internal use) In-house local application 15

16 16 History of.net Web Service Technologies

17 17 ASP.NET Web Services Introduced in.net 1.0 (2002) Look for.asmx Pretty much died when WCF was introduced (2005)! Transport Always HTTP[S] Data protocol SOAP (verbose XML dialect) WSDL XML file describing the service to custom tooling Easy to use from environments with WSDL tooling.net add service reference generates client-side code Difficult to use from other environments Producing and parsing complex SOAP messages Performance and scalability not great!

18 Windows Communication Foundation Introduced in.net Framework 3.0 (Visual Studio 2005) Last significant update in.net Framework 4.5 (Visual Studio 2012) More flexible & capable than ASMX Multiple network transports HTTP, TCP, named pipes, etc. Still SOAP-based, but improved performance Early REST capabilities shoehorned in to later versions Heavily configuration based Good and bad Simple to code, nightmare to configure! Could be fast, but scalability could be a BIG issue 18

19 ASP.NET Web API Introduced in.net Framework 4.0 (Visual Studio 2010) Now open source and actively developed Now supported by.net Framework and.net Core Total focus on RESTful web services Easy to learn and use Fully compatible with Synergy.NET Microsoft finally focused on performance! Fast and scalable, current best of breed Current state of the art for.net web services 19

20 20 RESTful Web Services

21 RESTful Web Services Representational State Transfer An architectural style, not a product, transport, or protocol A set of constraints to be used for creating web services Access & manipulate textual representations of resources in a uniform and stateless way Architectural goals Accessibility from any environment Simplicity through use of a uniform interface Performance and scalability RESTful implementations leverage various standards URI RFC 3986 HTTP RFC JSON RFC

22 Consistent Interface & Standard Operations URLs identifiy the type of entity being addressed Standards apply, naming conventions, etc. These URLs are known as routes or endpoints HTTP method used to access URL determines operation type Create, read, update, delete, etc. Inbound data passed in two ways Path parameters (in the URL) Body data (in the request body) Outbound data (if any) passed in the HTTP response body Completion status indicated by the HTTP response status code 22

23 URLs Identify Entity Being Addressed The collection of customer entities The specific customer with customer ID The collection of customers in California The collection of customers in California assigned to rep Each of these endpoints is mapped to a method in the code

24 HTTP Methods Identify Operation Type GET /api/customers Read all customers GET /api/customers/12345 Read one customer POST /api/customers Create new customer (primary auto assigned by service) New customer data passed in request body PUT /api/customers/12345 Create or update specific customer (all properties) Customer data passed in request body PATCH /api/customers/12345 Partial update specific customer (individual properties) Change instructions passed in request body DELETE /api/customers/12345 Delete specific customer 24

25 Data Passed via Request/Response Body GET, POST, and PUT PATCH 25

26 Completion Status Success status codes 200 OK Success Data is present in the response body 204 No content Success No data in response E.g., successful update or delete 201 Created A POST or PUT operation resulted in a new entity being created Location header contains URL Failure status codes 400 Bad request Invalid call to service Bad URL, missing headers, inappropriate data Client programming error 401 Unauthorized Authentication is required and the client is not authenticated 403 Forbidden The authenticated user does not have required permissions 404 Not found The requested resource does not exist 500 Internal server error Server programming error 26

27 Example Request and Response Request sent TO server POST /api/orders HTTP/1.1 Host: Content-Type: application/json Content-Length: 108 { account : , ponumber :19734, items :[{ sku : ABB701, quantity :1},{ sku : CRD1 00, quantity :10}]} Response returned FROM server HTTP/ Created Location: Programmers only ever see this in log files libraries do all the work! 27

28 Advantages of RESTful Web Services Simple to learn, build, and use URLs, HTTP, and basic CRUD operations Simple to write and document Completely open, reach more clients Less overhead Less duplication More standardized Testable Around 70% of public APIs are implemented as RESTful services 28

29 ASP.NET Web API Open source framework for building RESTful Web APIs No SOAP, no WSDL HTTP transport Preference for JSON, XML supported Closely related to ASP.

29 29 ASP.NET Web API Open source framework for building RESTful Web APIs No SOAP, no WSDL HTTP transport Preference for JSON, XML supported Closely related to ASP.NET MVC Models and controllers, familiar to many Convention over configuration Naming conventions, verbs map to HTTP methods, etc. Easy to learn, use, and deploy GREAT performance & scalability HUGE improvement over earlier technologies

30 30 Taking RESTful Services to the Next Level OData

OData V4 - Open Data Protocol An open protocol that allows the creation & consumption of queryable and interoperable RESTful APIs in a simple and standard way (Wikipedia) Initially a Microsoft

31 OData V4 - Open Data Protocol An open protocol that allows the creation & consumption of queryable and interoperable RESTful APIs in a simple and standard way (Wikipedia) Initially a Microsoft technology, now open source & independent Takes RESTful web services to a whole new level Expose a collection of entities Query that data in any way you want (examples follow) One OData endpoint may do hundreds of things Without coding individual functionality! 31

32 OData Query Mechanisms $select=field[,field, ] Specify the properties returned (like a sparse select) $filter=expression Filter the records that are returned $top=n and $skip=n Page result sets $count Return only the number of matching entities Return individual properties (JSON or raw data) Drill into related entities (multiple levels) 32

33 33 OData Query Filter Rows and Select Columns eq 'NV'&$select=CustomerNumber,Name

34 34 OData Query Filter Rows and Select Columns eq CA and CreditLimit gt 5000 &$select=customernumber, Name

35 Example OData Query Drill into Related Data $expand=rel_orders($select=ordernumber,dateordered; $expand=rel_orderitems($select=itemordered,quantityordered,unitprice; $expand=rel_itemordered($select=commonname,size))) 35

36 36 Why are RESTful Web Services Important to Your Business?

37 Why are RESTful Web Services Important to Your Business? Stand-alone app islands rarely satisfy an organizations needs Diverse best-of-breed apps on multiple platforms RWS APIs are THE standard way of integrating apps Most organizations use apps on multiple platforms Legacy apps, desktop apps, web apps, mobile apps, etc. APIs are the digital glue that join platforms together RWS are as open as it gets anything can talk HTTPS and JSON Web & mobile apps are REALLY important to most organizations RWS are THE standard way of exposing APIs Performance & scalability are REALLY important RWS are inherently fast & scalable (assuming devs don t screw up!) 37 Software development is expensive RWS are simple, quick & easy to implement & call And OData takes things to a whole new level! (more later)

38 38 Why the Big Focus on RESTful Web Services?

39 Why the Big Focus on RESTful Web Services? Enhancing UX is hugely important to many of you Fewer Synergy developers build UI using Synergy tools WinForms, WPF, UWP, Web Forms, MVC, HTML5, Xamarin Forms, etc. Often choose an alternate language for UI development The SERVER is the application, clients are just platform-specific views While TUI and Toolkit UI is no longer popular Huge investment in your code base Tightly coupled to your SDMS/RMS data High demand for exposing logic & data to new UI APIs are the future, web services are the best way expose APIs We have some new tools help you! 39

40 40

Framework for developing RESTful web APIs that expose Synergy data and business logic Binary code (NuGet packages) CodeGen templates Open source, including all dependencies Standards-based, building

41 Framework for developing RESTful web APIs that expose Synergy data and business logic Binary code (NuGet packages) CodeGen templates Open source, including all dependencies Standards-based, building on ASP.NET Core Web API OData Core EF Core Core Identity Highly efficient development Supplied libraries perform the heavy lifting Extensive use of code generation to implement feature-rich data services Fill in the gaps with hand-crafted code Fast and scalable 41

42 Sessions To Pay Special Attention To Demystifying.NET Standard and.net Core Setting the technology stage (Steve Ives, Wednesday, 9am) Introducing the Harmony Core Open Source Project So what s it all about? (Jeff Greene, Wednesday, 10.45am) Leveraging EF Core to Access Synergy Data What s happening under the hood? (Jeff Greene, Wednesday, 1.30pm) Building RESTful Web Services with Harmony Core How can I do this in my environment? (Steve Ives, Wednesday, 4pm) Post-Conference Workshop Use it all hands on! (Steve Ives, Friday, 9am until we finish, no later than 3pm!) 42

43 Introduction to RESTful Web Services Who has the first question? 43

Building RESTful Web Services with. Presented by Steve Ives

Building RESTful Web Services with Presented by Steve Ives We ve talked about what it is We ve talked about what it does Let s talk about how to use it Requirements & Obtaining Visual Studio 2017 15.8