Salesforce-MuleSoft-Developer-I Questions and Answers

This helps CloudHub to dynamically allocates a port at deployment time.

MuleSoft Doc Ref : https://docs.mulesoft.com/mule-runtime/4.3/deploy-to-cloudhub#prerequisites

Correct answer is Array.

Flatten turns a set of subarrays (such as [ [1,2,3], [4,5,[6]], [], [null] ]) into a single, flattened array (such as [ 1, 2, 3, 4, 5, [6], null ]).

This example defines three arrays of numbers, creates another array containing those three arrays, and then uses the flatten function to convert the array of arrays into a single array with all values.

Source

%dw 2.0

output application/json

var array1 = [1,2,3]

var array2 = [4,5,6]

var array3 = [7,8,9]

var arrayOfArrays = [array1, array2, array3]

---

flatten(arrayOfArrays)

Output

[ 1,2,3,4,5,6,7,8,9 ]

Correct answer is as below. Attributes in the incoming xml payload are always accessed using @.Similarly *item is required as we have multiple items in the request

%dw 2.0

output application/csv

---

payload.sale.*item map ((value, index) -> {

index: index,

sale: value.@saleId,

itemName: value.desc,

itemPrice: (value.quantity) * (value.price),

item: value.@itemId

} )

Correct answer is Merges elements of two lists (arrays) into a single list

MuleSoft Doc Reference : https://docs.mulesoft.com/mule-runtime/4.3/dw-core-functions-zip

Query parameters are a defined set of parameters attached to the end of a url. They are extensions of the URL that are used to help define specific content or actions based on the data being passed. To append query params to the end of a URL, a ‘?’ Is added followed immediately by a query parameter.

To add multiple parameters, an ‘&’ is added in between each.

Hence coming back to question, endpoint would return Patients with name as John and (and is very important here) surname as Bell

The APIkit Router is a key message processor that validates requests against the provided definition, enriches messages (for example by adding default values to the messages) and routes requests to a particular flow. Also, the Router raises errors messages if errors occurs while routing, validating or processing the user request.

Correct answer is Specify throttling , security and other policies

MuleSoft Doc Ref : https://docs.mulesoft.com/api-manager/2.x/api-gateway-capabilities-mule4

API Gateway is responsible for below functions.

1) Determine which traffic is authorized

2) Meter the traffic

3) Logs transaction

4) Apply throttling and other policies (Not specifying. These are specified in API Manager)

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client-id-required enforces clients to add client_id and client_secret.

Please refer to below steps.

• Add a section called traits: at the root level to define query parameters:
• traits:
• - client-id-required:
• queryParameters:
• client_id:
• type: string
• client_secret:
• type: string
• 2) Reference the trait in each of the methods to specify that each of the methods require these query parameters. After each method in the RAML file, add is: [client-id-required]. For example:
• /users:
• get:
• is: [client-id-required]
• description: Gets a list of JSONPlaceholder users.

File is not updated when FTP read operations is performed.

MuleSoft Doc Ref : https://docs.mulesoft.com/file-connector/1.3/file-read

Allowed methods is an optional configuration. If nothing is specified then all HTTP methods are supported.

Rest all are mandatory.

This is a trcik question. On complete phase pyalod consists of summary of records processed which gives insight on which records failed or passed. Hence option 4 is correct answer

MuleSoft Documentation Reference : https://docs.mulesoft.com/mule-runtime/4.3/batch-processing-concept#on-complete

Lets revise few concepts RAML which can help us to find the answer of this question.

URI Parameters

Lets have a look at below example.

• /foos:
• /{id}:
• /name/{name}:

Here, the braces { } around property names define URI parameters. They represent placeholders in each URI and do not reference root-level RAML file properties as we saw above in the baseUri declaration. The added lines represent the resources /foos/{id} and /foos/name/{name}.

Query Parameters

Now we'll define a way to query the foos collection using query parameters. Note that query parameters are defined using the same syntax that we used above for data types:

• /foos:
• get:
• description: List all Foos matching query criteria, if provided;
• otherwise list all Foos
• queryParameters:
• name?: string
• ownerName?: string

Based on the above information , below is the only option which defines storeid as uri parameter and department as query parameter.

• /{storeId}:
• get:
• queryParameter:
• department:

Mule event is correct answer. Mule event has two parts which are as follows

1) Message (which contains payload and attributes like headers and query/uri parameters

2) Variables

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Pick First is not valid type. Rest all are valid type of event processor.

Choice : https://docs.mulesoft.com/mule-runtime/4.3/choice-router-concept

Round Robin : https://docs.mulesoft.com/mule-runtime/4.3/round-robin

First Successful : https://docs.mulesoft.com/mule-runtime/4.3/first-successful

You can define your own DataWeave functions using the fun declaration in the header of a DataWeave script. Sample is as below. ----------------------------------------

%dw 2.0

output application/json

fun toUpper(aString) = upper(aString)

---

toUpper("hello")

MuleSoft Doc Ref : https://docs.mulesoft.com/mule-runtime/4.1/dataweave-functions

Sequence can be described as follows.

* When web client sends the request , it sends payload as Blue (mentioned in question)

* In first iteration this will go to default choice , which sets payload to Red

* Via default route , flow will call itself with payload as Red

* In second iteration , as payload is Red , it will go to first route in choice router which will set payload to Blk and second iteration will end returning back payload as Blk to first iteration.

* This Blk will be again set to payload and first iteration will end returning back response as Blk

URL parameters are always accessed using { } like => {customerID}

Correct answer is [[5, 10, 15, 20], 5]

Key thing to note here is that any changes made to payload in for each loop are not available outside for each scope where as variable value updated in for each loop is visible out side for each loop too.

In this example , sequence can be described as follows

1) Payload is set to the value [5, 10, 15, 20]

2) Variable is set to the value of 1

3) For each loop is executed four times and in each loop payload value is updated to append "Req" and variable is count is increased by 1

4) Once control comes out of for each , payload changes made within for each are not visible. Hence payload at this point of time is equal to payload available before entering for each loop which was  [5, 10, 15, 20]. Similarly variable value updated in for each loop is also available outside hence variable value is 5 as it was updated in loop.

5) Hence correct answer is [[5, 10, 15, 20], 5]

For Each Scope

The For Each scope splits a payload into elements and processes them one by one through the components that you place in the scope. It is similar to a for-each/for loop code block in most programming languages and can process any collection, including lists and arrays. The collection can be any supported content type, such as application/json, application/java, or application/xml.

General considerations about the For Each scope:

By default, For Each tries to split the payload. If the payload is a simple Java collection, the For Each scope can split it without any configuration. The payload inside the For Each scope is each of the split elements. Attributes within the original message are ignored because they are related to the entire message.

For Each does not modify the current payload. The output payload is the same as the input.

For non-Java collections, such as XML or JSON, use a DataWeave expression to split data. Use the Collection field for this purpose.

lookup(String, Any, Number)

This function enables you to execute a flow within a Mule app and retrieve the resulting payload.

It works in Mule apps that are running on Mule Runtime version 4.1.4 and later.

Similar to the Flow Reference component (recommended), the lookup function enables you to execute another flow within your app and to retrieve the resulting payload. It takes the flow’s name and an input payload as parameters. For example, lookup("anotherFlow", payload) executes a flow named anotherFlow.

Correct answer is

lookup( "createCustomerObject", {first: "Aice, last: "Green"})

MuleSoft Documentation Reference : https://docs.mulesoft.com/mule-runtime/4.3/dw-mule-functions-lookup

Correct answer is APP: API RESOURCE NOT FOUND

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1) A web client submits the request to the HTTP Listener.

2) The HTTP Request throws an "HTTP:NOT_FOUND" error, execution halts.

3) The On Error Propagate error Handler handles the error. In this case ,HTTP:NOT_FOUND error is mapped to custom error APP:API_RESOURCE_NOT_FOUND. This error processor sets payload to APP:API_RESOURCE_NOT_FOUND.

4) “APP:API_RESOURCE_NOT_FOUND. ” is the error message returned to the requestor in the body of the HTTP request with HTTP Status Code: 500

Reference Diagram:

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Choice Router

The Choice router dynamically routes messages through a flow according to a set of DataWeave expressions that evaluate message content. Each expression is associated with a different routing option. The effect is to add conditional processing to a flow, similar to an if/then/else code block in most programming languages.

Only one of the routes in the Choice router executes, meaning that the first expression that evaluates to true triggers that route’s execution and the others are not checked. If none of the expressions are true, then the default route executes.

Properties of

PropertyDescription

Expression (expression)

Expression in DataWeave language to evaluate input.If the expression evaluates to true, this routing option is used:

Mulesoft Doc Ref : https://docs.mulesoft.com/mule-runtime/4.3/choice-router-concept

With respect to above information ,

Option 1 is the correct syntax as others are incorrect because of below reasons

* Single = is not the correct syntax to validate the condition. It should be ==

* If keyword is not required in when condition.

Correct answer is Not needed as dw::core module is included by default. We don't need to include it explicitly

Correct answer is The city is #[payload.City]

Answer can get confused with the option #["The city is" ++ payload.City] But note that this option will not print the space between is and city name. This will print The city isPune

The HTTP 415 Unsupported Media Type client error response code indicates that the server refuses to accept the request because the payload format is in an unsupported format. The format problem might be due to the request's indicated Content-Type or Content-Encoding , or as a result of inspecting the data directly. In this case as per RAML specification data is expected in application/json and in request Content-Type is set as "text/plain" which is incorrect. Hence solution is set the request Content-Type header to application/json

https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/415

WSDL is used to define the contract in case of SOAP . RAML/OAS is used to REST services

Application properties can be defined in .yaml or in .properties file.

MuleSoft Doc Ref : https://docs.mulesoft.com/mule-runtime/4.3/configuring-properties#supported_files

Correct answer is String is not blank.

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Here’s specifically what is happening here:

1) Payload is successfully set to “Start”

2) The Is Blank String validator creates an Error Object because the payload is string "Start". Execution stops

#[error.description] = “String is not blank”

3) Because no error handler is defined, the Mule default error handler handles the error. Remember, at its heart, the Mule Default Error handler is an error handling scope with just an on error propagate

4) “String is not blank” is the error message returned to the requestor in the body of the HTTP requestHTTP Status Code: 500

Reference Diagram:

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Correct answer is Save the payload from the Database SELECT operation to a variable

Response from HTTP request will override the payload and hence response of database SELECT can be lost. Best way to preserve is to assign payload of first operation to variable using TransformMessage.

Variables are stored under Mule event. Please refer to below image for the hierarchy .

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Correct answer is as below.After all processing routes have finished execution, the Scatter-Gather component creates a new Mule event that combines all resulting Mule events from each route, and then passes the new Mule event to the next component in the flow.

{

"0": {

"attributes": ...,

"payload": "100"

},

"1": {

"attributes": ...,

"payload": "200"

}

}

Bottom of Form

To include property. To keep the API definition concise, you can include external content, such as documentation, schemas, and frequently used patterns outside the definition itself. The parser interprets !include as if the content of the externally-hosted file or a URL were declared in-line.

To use the fragments in RAML you have to include the exact path(copy the path) of that fragment you want to use as shown below

Option 3 is the correct as correct syntax is

examples: !include examples/StudentExample.raml

Correct answer is Modify the API implementation to use auto-discovery to register with API Manager

API Autodiscovery

Configuring autodiscovery allows a deployed Mule runtime engine (Mule) application to connect with API Manager to download and manage policies and to generate analytics data. Additionally, with autodiscovery, you can configure your Mule applications to act as their own API proxy.

When autodiscovery is correctly configured in your Mule application, you can say that your application’s API is tracked by (green dot) or paired to API Manager. You can associate an API in a Mule setup with only one autodiscovery instance at a given time.

MuleSoft Doc Ref : https://docs.mulesoft.com/api-manager/2.x/api-auto-discovery-new-concept

Correct answer is Change the method attributes value to "POST".

It can be fixed in either of the two ways as below.

1) Changing method attribute to POST in ClientRequestFlow

2) Setting allowedMethods as PUT in ShippingFlow (but doesn't fit as question mentions about changing ClientRequestFlow)

Correct answer is vars."customer"."firstName"

Please note that you can also access firstName using this syntax vars.customer.firstName.

Mule Ref Doc : Variables in Mule Apps | MuleSoft Documentation

Option 1 is the only correct choice due to two reasons. 1) Concatenation is always with ++ sign and not with + sign which makes option 2 and 3 wrong 2) hearders can be accessed with attributes. headers and not with only headers which makes option 4 incorrect

Returns an array that is the result of applying a transformation function (lambda) to each of the elements.

MuleSoft Doc Ref : https://docs.mulesoft.com/mule-runtime/4.3/dataweave-cookbook-map

The map operator is a function in Dataweave which iterates over the items in an array and outputs them into a new array. It basically accepts input as a list of items in an array and manipulates the items in the array in order to form a new array as an output.

I have created below chart for your easier understanding:

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Option 1 is the correct syntax

Correct syntax to use where clause is WHERE city = :city AND state = :state

This question validates knowledge on using dynamic queries in DB select operation.

Configure Dynamic Queries in the Select Operation

When you need to parameterize not only the WHERE clause but also parts of the query itself (for example, queries that compare tables that depend on a condition, or complex queries for which the project table columns need to vary), you can configure dynamic queries.

In the following example, you configure a dynamic query by using a full expression with a string in which the table depends on a variable $(vars.table). Although some of the query text is dynamic ("SELECT * FROM $(vars.table)), the WHERE clause still defines the WHERE condition using input parameters: in this case, WHERE name = :name.

In your Studio flow, select the Select operation.

In the operation configuration screen, set the SQL Query Text field to SELECT * FROM $(vars.table) WHERE name = :name.

Set the Input Parameters field to {'name' : payload}.

The following screenshot shows the configuration in Studio:

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Figure 3. Dynamic query configuration

In the XML editor, the  configuration looks like this:

• #["SELECT * FROM $(vars.table) WHERE name = :name"]
• #[{'name' : payload}]

You can apply input parameters only to parameters in a WHERE clause. To modify any other part of the query, use the DataWeave interpolation operator.

Mule Ref Doc: Query a Database Examples - Mule 4 | MuleSoft Documentation

Transform Message Add write_date is coverting payload in JSON format and same JSON payload is avaialble to file write processor. However, if the payload is a different format (for example, not CSV) , you can place the transformation inside the Write operation to generate content that will be written without producing a side effect on the message in transit. This is not done in this case. By default, the connector writes whatever is in the message payload. Hence JSON payload will be written to file.

Error in validation component will get processed by Processer level On Error Propagate block and then error will be rethrown which will get processed by flow level error handler which will set payload to "Error- main flow". Hence correct answer is Error - main flow

1) Request is received by HTTP listener

2) Try scope gets executed

3) The validator component in the Try scope creates an Error Object because the payload is not null.

4) The On Error Propagate handles the error. The payload is set to “Error – Try scope”

6) “Error – Try scope” is returned to the 'On Error Continue' block. Main flow execution stops. Payload is set to "Error - main flow"

7) “Error - main flow” is returned to the requestor in the body of the HTTP request. HTTP Status Code: 200

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Reference Diagram though not exactly same, conditions are similar. They will help you answer any new question on error handling in real exam:

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https://docs.mulesoft.com/mule-runtime/4.3/on-error-scope-concept#on-error-continue

Correct answer is Request access to the API in Anypoint Exchange. This way we can get clientId and Client secret which we can use to access the API

Correct answer is System layer

System APIs provide a means for insulating the data consumers from the complexity or changes to the underlying backend systems.

MuleSoft recommends three-layered approach to API-led connectivity, highlighting the three layers:

* System APIs

* Process APIs

* Experience APIs

System APIs are the core systems of record underlying core systems of record (e.g. ERPs, key customer and billing systems, databases, etc.). Process APIs allow you to define a common process which the organization can share, and these APIs perform specific functions, provide access to non-central data, and may be built by either Central IT or Line of Business IT. And finally, the Experience APIs are the means by which data can be reconfigured so that it is most easily consumed by its intended audience, all from a common data source.

The three-layered structure allows for a seamless flow of data from systems of record to new experiences, and allows for reusability of assets rather than point to point connections. This approach provides a distributed and tailored approach to architecture, greater flexibility through loose coupling, and deeper operational visibility into what is being built.

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In this case as outbound call is made using HTTP: POST /child , all attributes will be replaced by this invocation. Hence query parameter will not be accessible at logger. Hence correct answer is option 2

Correct Answer: Response body: "Error" Default response status code: 200.

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1) Payload is successfully set to “Success – Started Flow”

2) When HTTP Request throws an error, execution halts

#[error.description] = “ABC"

#[error.errorType] = "XYZ"

3) The On Error Continue scope handles the error. When On Error Continue scope is invoked, all the processors in error block are executed and success response is sent back to the client with payload which is set in error flow. In this case payload is set to "Error" value in error block.

4) “Error” is returned to the requestor in the body of the HTTP request with HTTP Status Code: 200 as On error continue always sends success error code.

Reference Diagram:

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Correct answer is as below. In this case address will be stored in a variable. Hence payload will not be overwritten and will contain order details

{

orderkey: "payload.order",

addresskey: "vars.address"

}

Correct answer is Creates a mock service for an API

API Notebook is an open source, shareable web application for API documentation, interactive API tutorial and example generatation, and a client for your API endpoints. Using API Notebook, you can make requests and quickly transform the responses into readable format. However it cannot be used to mock service for an API.

MuleSoft Doc Ref : https://docs.mulesoft.com/api-manager/1.x/api-notebook-concept