Merge pull request #5670 from SasinduDilshara/handling-csv-streams

Ad bbe for parsing csv byte streams

examples/csv-streams-to-record-arrays/csv_streams_to_record_array.bal

@@ -0,0 +1,38 @@
+import ballerina/data.csv;
+import ballerina/io;
+
+type Book record {
+    string name;
+    string author;
+    decimal price;
+    string publishedDate;
+};
+
+type BookMinimal record {|
+    string name;
+    string author;
+|};
+
+const csvFilePath = "./files/csv_file.csv";
+
+public function main() returns error? {
+    // Write a CSV file.
+    check io:fileWriteCsv(csvFilePath, [["name", "author", "price", "publishedDate"],
+                                        ["Effective Java", "Joshua Bloch", "45.99", "2018-01-01"],
+                                        ["Clean Code", "Robert C. Martin", "37.5", "2008-08-01"]]);
+
+    // Read the CSV file as a byte stream.
+    stream<byte[], error?> bookStream = check io:fileReadBlocksAsStream(csvFilePath);
+
+    // Parse as CSV byte stream to an array of records.
+    Book[] bookArray = check csv:parseStream(bookStream);
+    io:println(bookArray);
+
+    bookStream = check io:fileReadBlocksAsStream(csvFilePath);
+
+    // Parse the CSV byte stream as an array of records with data projection.
+    // Here only the fields specified in the target record type (`name` and `author` fields)  
+    // are included in the constructed value. 
+    BookMinimal[] briefBookArray = check csv:parseStream(bookStream);
+    io:println(briefBookArray);
+}

examples/csv-streams-to-record-arrays/csv_streams_to_record_array.md

@@ -0,0 +1,7 @@
+# Parse CSV byte stream to Ballerina record array
+
+The Ballerina `data.csv` library allows parsing the CSV byte streams as arrays of Ballerina records, making it easier to process CSV data directly from `streams`. This functionality supports data projection, enabling developers to extract and map only the required fields to the target `record` type.
+
+::: code csv_streams_to_record_array.bal :::
+
+::: out csv_streams_to_record_array.out :::

examples/csv-streams-to-record-arrays/csv_streams_to_record_array.metatags

@@ -0,0 +1,2 @@
+description: This BBE demonstrates the parsing of CSV byte streams into Ballerina record arrays, both with and without data projection.
+keywords: ballerina, ballerina by example, bbe, csv, csv byte streams, csv streams, record, record array, parseStream, csv data module, data.csv, data projection, csv to stream

examples/csv-streams-to-record-arrays/csv_streams_to_record_array.out

@@ -0,0 +1,3 @@
+$ bal run csv_streams_to_record_array.bal
+[{"name":"Effective Java","author":"Joshua Bloch","price":45.99,"publishedDate":"2018-01-01"},{"name":"Clean Code","author":"Robert C. Martin","price":37.5,"publishedDate":"2008-08-01"}]
+[{"name":"Effective Java","author":"Joshua Bloch"},{"name":"Clean Code","author":"Robert C. Martin"}]

examples/index.json

@@ -4739,6 +4739,13 @@
         "verifyBuild": true,
         "verifyOutput": true,
         "isLearnByExample": true
+      },
+      {
+        "name": "Parse CSV byte streams to records",
+        "url": "csv-streams-to-record-array",
+        "verifyBuild": true,
+        "verifyOutput": true,
+        "isLearnByExample": true
       }
     ]
   },