The document summarizes a MuleSoft meetup event discussing RAML and Dataweave functions. The meetup included introductions by the organizers and two speakers, and covered topics such as RAML best practices including spec-driven development, API design considerations, modularization, mocking, resources and naming conventions, and HTTP codes and verbs. It also provided an overview of the Dataweave expression language and examples of how to use functions for data transformation, flow control, logging, lookups, lambda functions, and iterators.

1. [27-02-2021]
[Kochi] MuleSoft Meetup Group
RAML, Dataweave functions.

2. 2
Introductions
● API + RAML Best Practices
● The Power of dataweave
Agenda

3. 3
Organizers
Supriya Pawar
Technical Lead at
Accenture
About the organizer:
 Kochi MuleSoft Meetup Leader.
 7+ Years of Experience in Integrations and API Technologies.
 Certified MuleSoft Developer, Integration Architect and platform Architect.

4. 4
Speakers
Sanjana Mishra
Senior Developer at Accenture
About the Speaker:
 Having 5+ years of overall experience building integration solutions.
 Certified MuleSoft Developer And Platform Architect.
About the Speaker:
 5+ Years of Experience in Integrations and API Technologies.
 Certified MuleSoft Developer, Integration Architect and platform
Architect.
Sumit Ahuja
Senior Developer at Accenture

5. RAML + API Best Practices

6. 6
What is RAML ? Why we use it ?

7. Best Practices in RAML ?
● Use Spec Driven Development
● Think about the API
● Modularize and Reuse
● Mocking
● Resources and Naming
● HTTP Codes and Verbs
7

8. 8

9. Use Spec Driven Development
● Use Design Patterns/ Code Reuse.
● Mock and get User Feedback.
● Make Necessary Changes.
● Start Coding to the Spec and don't deviate.
9

10. Benefits of Spec Driven
● Parallelize the development process
● Improves understanding of the whole
● Guide Development
10

11. Think about the API
11

12. Think of a Long term
● Your API is a Contract
● Versioning is not a Solution
● You can pay a little now , or much more Later.
● You need to think things through
● Mindset is everything
12

13. Think Things Through
● Who is your API for ?
● What type of API are you building ?
● How are you going to maintain your API ?
● How are you going to document your API ?
● How are you going to lets users interact with your API ?
● How are you going to manage authentication, provisioning and developer security ?
● How are going to protect your servers against attacks etc ?
● How are you going to manage support ?
13

14. Who Will Be Using Your API?
14

15. Versioning – A Necessary Evil
● Problems with versioning :
○ Backward Incompatibilities
○ Multiple services to maintain
○ Multiple systems to support
○ Creates Confusion among developers
15

16. Modularize and Reuse (RAML Inheritance)
● This can be Best achieved using the below two features of RAML :
○ Resource Types
■ ResourceType is basically a template that is used to define the descriptions, methods, and parameters that
can be used by multiple resources without writing the duplicate code or repeating code.
○ Traits
■ Traits is like function and is used to define common attributes for HTTP method (GET, PUT, POST,
PATCH, DELETE, etc) such as whether or not they are filterable, searchable, or pageable.
16

17. Defining Resource Types
17

18. Calling resource Types from RAML
18

19. Declaring Traits
19

20. Calling Traits from Resource Types and Resources
20

21. Mocking
● The API mocking service enables you simulate the behavior of an API specification. The
mocking service provides a test link to an API. The mocking service returns the responses
(both HTTP status codes and example payloads) that are defined in your API specification
and is valuable for testing or for simply exploring how your API behaves.
● Simulate a Call to an API using an Internal URL
● Simulate a Call to an API using a Public URL
21

22. Simulate a Call to an API using an Internal URL
22

23. Simulate a Call to an API using a Public URL
23

24. Resources and Naming
● Use of camelCase for placeholders in URL.
● Use nouns in lowercase to represent a resource, for resources with multiple words, use
lowercase for all the words or use '-' (dash) in between the words and make it readable.
● Use of Parameters:
○ URI Parameter
○ Query Parameter
24

25. Example
25

26. HTTP Codes
● 1xx : Informational
● 2xx : Success
● 3xx : Redirect
● 4xx : Client error
● 5xx : Server error
26

27. HTTP verbs
● GET
● PUT
● PATCH
● POST
● DELETE
27

28. Power of Dataweave

29. Overview
● DataWeave is the MuleSoft expression language for accessing and transforming data within
mule apps
● Not only limited to data transformation
● Provides module or lambda function creation support
● Supports flow control and Scope Operations
● Provides feasibility for streaming for efficient processing of large documents without
overloading memory
● Datasense or preview mapping to avoid possible errors
29

30. Data Formats
30

31. 31
● Sample snippet to read a XLS file using DWL vs Java
Read Function

32. Logging
32
● Use this function to help with debugging DataWeave scripts

33. 33
● Flow control operations such as If else , do , else if can be used
Flow Control and Scope Operations

34. Lookup Operation
● Enables you to execute a flow from within dataweave and use the payload for further
processing
● In case the flow to be executed has a external connection you can provide a timeout value.
● Note : The lookup function does not support calling subflow
34

35. 35
● The Below example creates the lambda function to check validity by comparing dates
Creating Lambda Functions

36. Creating Lambda Functions (Using Variable)
36
● The Below example create executes the lambda function and stores in variable
checkValildity.

37. Using Map Iterator
37
● Use to iterate over array or list of values

38. Map Object
38
● Use to iterate over key value pairs of objects

39. Filter
39
● The value inside array can be also referred as $
● To filter an array as per given function

40. Get Set from Objects
40

41. 41
● The accumulator can be referred as $$
● The value in the array can be referred as $
Reduce

42. 42
● Combine set of subarrays into single array
● It flattens only the first level of subarrays and omits empty subarrays
Flatten

43. 43
● Iterates over an object and returns an array of keys, values, or indices from the object.
● It is an alternative to mapObject which is similar but returns an object, instead of an array.
Pluck

44. keysOf – Mule 4.3
44

45. valuesOf – Mule 4.3
45

46. firstWith – Mule 4.3
46

47. 47
● How to get a Object from Map operator
Quick Hacks

48. 48
● How to dynamically populate a value
Quick Hacks

49. Introduce yourself to your neighbor
Networking time

50. Thank you