MuleSoft DataWeave: Reading From the File
Follow along with this brief tutorial to follow an example of how to read data from files using MuleSoft DataWeave.
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Join For FreeBefore we start, let's go over the following:
- readurl (): It is dw-core-function and returns parsed content from source at given classpath-based url. readurl("classpath-based url","contentType").
- dynamic selector[()]: Return the value of expression passed in parentheses of dynamic selector [()].
Example of Reading Data From Files
The file in use here is zipcode.json, which has zip codes for different cities in India. It is available at classpath "/src/main/resources/".
Example 1:
Reading data from a file can be achieved by using readUrl() in DataWeave.
Data in the "zipcode.json" file is as follows:
JSON
{
"Indore" : "455001" ,
"Pune" : "411002",
"Bhopal" : "462003",
"Banglore" : "56004"
}DataWeave Code, to cath parsed value in dwl variable and map it to a field:
JSON
%dw 2.0
output application/json
var zipcodes = readUrl("classpath://zipcode.json" , "application/json")
---
{
"usingVar" : zipcodes,
"directlyUsingURL" : readUrl("classpath://zipcode.json" , "application/json")
}Output:
JSON
{
"usingVar": {
"Indore": "455001",
"Pune": "411002",
"Bhopal": "462003",
"Banglore": "56004"
},
"directlyUsingURL": {
"Indore": "455001",
"Pune": "411002",
"Bhopal": "462003",
"Banglore": "56004"
}
}Example 2:
Mapping a field in response from parsed data of the file can be achieved in a single transform node using "readUrl()" and "dynamic selector [()] for single value".
Data in the "zipcode.json" file:
JSON
{
"Indore" : "455001" ,
"Pune" : "411002",
"Bhopal" : "462003",
"Banglore" : "56004"
}Input payload:
JSON
[
{
"city": "Indore"
},
{
"city": "Bhopal"
}
]DataWeave code:
JSON
%dw 2.0
output application/json
var zipcodes = readUrl("classpath://zipcode.json" , "application/json")
---
payload map ((item, index) -> {
"City": item.city,
"Zipcode": zipcodes[item.city]
})Output:
JSON
[
{
"City": "Indore",
"Zipcode": "455001"
},
{
"City": "Bhopal",
"Zipcode": "462003"
}
]Thanks!
MuleSoft
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