Initial add backend stuff

csv/csv.go

@@ -0,0 +1,123 @@
+package csv
+
+import (
+	"encoding/csv"
+	"errors"
+	"fmt"
+	"net/http"
+	"reflect"
+	"strings"
+)
+
+func WriteCSVtoHTTP(w http.ResponseWriter, csv string, filename string) {
+	w.Header().Set("Content-Type", "text/csv")
+	w.Header().Set("Content-Disposition", "attachment; filename="+filename+".csv")
+
+	w.Write([]byte(csv))
+}
+
+func MakeCSV(headers []string, records [][]string) (string, error) {
+	if len(records) > 0 {
+		if len(headers) != len(records[0]) {
+			return "", errors.New("data contains more columns then specified by headers")
+		}
+	}
+
+	// Write to CSV
+	var csvBuilder strings.Builder
+	writer := csv.NewWriter(&csvBuilder)
+
+	// Write headers
+	if err := writer.Write(headers); err != nil {
+		return "", fmt.Errorf("failed to write headers: %v", err)
+	}
+
+	// Write records
+	for _, record := range records {
+		if err := writer.Write(record); err != nil {
+			return "", fmt.Errorf("failed to write record: %v", err)
+		}
+	}
+
+	writer.Flush()
+	if err := writer.Error(); err != nil {
+		return "", fmt.Errorf("csv writer error: %v", err)
+	}
+
+	return csvBuilder.String(), nil
+}
+
+func StructToCSV(data any) (string, error) {
+	val := reflect.ValueOf(data)
+	if val.Kind() != reflect.Slice {
+		return "", fmt.Errorf("input must be a slice of structs")
+	}
+
+	if val.Len() == 0 {
+		return "", nil
+	}
+
+	var headers []string
+	var records [][]string
+
+	// Get the first element to determine struct fields
+	first := val.Index(0)
+	if first.Kind() == reflect.Ptr {
+		first = first.Elem()
+	}
+
+	if first.Kind() != reflect.Struct {
+		return "", fmt.Errorf("slice elements must be structs or pointers to structs")
+	}
+
+	// Get field names as headers
+	t := first.Type()
+	for i := 0; i < t.NumField(); i++ {
+		field := t.Field(i)
+		// Use json tag if present, otherwise use field name
+		tag := field.Tag.Get("json")
+		if tag != "" && tag != "-" {
+			headers = append(headers, tag)
+		} else {
+			headers = append(headers, field.Name)
+		}
+	}
+
+	// Convert each struct to a record
+	for i := 0; i < val.Len(); i++ {
+		item := val.Index(i)
+		if item.Kind() == reflect.Ptr {
+			item = item.Elem()
+		}
+
+		var record []string
+		for j := 0; j < item.NumField(); j++ {
+			fieldVal := item.Field(j)
+			record = append(record, fmt.Sprintf("%v", fieldVal.Interface()))
+		}
+		records = append(records, record)
+	}
+
+	// Write to CSV
+	var csvBuilder strings.Builder
+	writer := csv.NewWriter(&csvBuilder)
+
+	// Write headers
+	if err := writer.Write(headers); err != nil {
+		return "", fmt.Errorf("failed to write headers: %v", err)
+	}
+
+	// Write records
+	for _, record := range records {
+		if err := writer.Write(record); err != nil {
+			return "", fmt.Errorf("failed to write record: %v", err)
+		}
+	}
+
+	writer.Flush()
+	if err := writer.Error(); err != nil {
+		return "", fmt.Errorf("csv writer error: %v", err)
+	}
+
+	return csvBuilder.String(), nil
+}