Documentation
¶
Overview ¶
Package csvpputil provides utility functions for converting CSV++ data to other formats such as JSON and YAML.
JSON Streaming Output ¶
For large JSON files, use JSONArrayWriter to stream records directly to the output:
w := csvpputil.NewJSONArrayWriter(out, headers)
for {
record, err := reader.Read()
if err == io.EOF {
break
}
if err != nil {
return err
}
if err := w.Write(record); err != nil {
return err
}
}
if err := w.Close(); err != nil {
return err
}
YAML Streaming Output ¶
For YAML output, use YAMLArrayWriter:
w := csvpputil.NewYAMLArrayWriter(out, headers)
for _, record := range records {
if err := w.Write(record); err != nil {
return err
}
}
if err := w.Close(); err != nil {
return err
}
Convenience Functions ¶
For small to medium datasets, use the Marshal or Write functions:
data, err := csvpputil.MarshalJSON(headers, records) data, err := csvpputil.MarshalYAML(headers, records) err := csvpputil.WriteJSON(w, headers, records) err := csvpputil.WriteYAML(w, headers, records)
Index ¶
- func MarshalJSON(headers []*csvpp.ColumnHeader, records [][]*csvpp.Field, ...) ([]byte, error)
- func MarshalYAML(headers []*csvpp.ColumnHeader, records [][]*csvpp.Field) ([]byte, error)
- func WriteJSON(w io.Writer, headers []*csvpp.ColumnHeader, records [][]*csvpp.Field, ...) error
- func WriteYAML(w io.Writer, headers []*csvpp.ColumnHeader, records [][]*csvpp.Field) error
- type JSONArrayWriter
- type JSONArrayWriterOption
- type YAMLArrayWriter
Examples ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func MarshalJSON ¶
func MarshalJSON(headers []*csvpp.ColumnHeader, records [][]*csvpp.Field, opts ...JSONArrayWriterOption) ([]byte, error)
MarshalJSON converts CSV++ records to JSON bytes. The output is a JSON array of objects, where each object represents a record.
Example ¶
headers := []*csvpp.ColumnHeader{
{Name: "name", Kind: csvpp.SimpleField},
{Name: "age", Kind: csvpp.SimpleField},
}
records := [][]*csvpp.Field{
{{Value: "Alice"}, {Value: "30"}},
{{Value: "Bob"}, {Value: "25"}},
}
data, err := csvpputil.MarshalJSON(headers, records, csvpputil.WithDeterministic(true))
if err != nil {
log.Fatal(err)
}
fmt.Println(string(data))
Output: [{"name":"Alice","age":"30"},{"name":"Bob","age":"25"}]
func MarshalYAML ¶
MarshalYAML converts CSV++ records to YAML bytes. The output is a YAML array where each element is a record.
Example ¶
headers := []*csvpp.ColumnHeader{
{Name: "name", Kind: csvpp.SimpleField},
{Name: "age", Kind: csvpp.SimpleField},
}
records := [][]*csvpp.Field{
{{Value: "Alice"}, {Value: "30"}},
{{Value: "Bob"}, {Value: "25"}},
}
data, err := csvpputil.MarshalYAML(headers, records)
if err != nil {
log.Fatal(err)
}
fmt.Print(string(data))
Output: - name: Alice age: "30" - name: Bob age: "25"
func WriteJSON ¶ added in v0.0.4
func WriteJSON(w io.Writer, headers []*csvpp.ColumnHeader, records [][]*csvpp.Field, opts ...JSONArrayWriterOption) error
WriteJSON writes CSV++ records as a JSON array to the provided writer. The output is a JSON array of objects, where each object represents a record.
Example ¶
headers := []*csvpp.ColumnHeader{
{Name: "name", Kind: csvpp.SimpleField},
{Name: "score", Kind: csvpp.SimpleField},
}
records := [][]*csvpp.Field{
{{Value: "Alice"}, {Value: "100"}},
{{Value: "Bob"}, {Value: "85"}},
}
if err := csvpputil.WriteJSON(os.Stdout, headers, records, csvpputil.WithDeterministic(true)); err != nil {
log.Fatal(err)
}
Output: [{"name":"Alice","score":"100"},{"name":"Bob","score":"85"}]
func WriteYAML ¶ added in v0.0.4
WriteYAML writes CSV++ records as a YAML array to the provided writer. The output is a YAML array where each element is a record.
Example ¶
headers := []*csvpp.ColumnHeader{
{Name: "name", Kind: csvpp.SimpleField},
{Name: "score", Kind: csvpp.SimpleField},
}
records := [][]*csvpp.Field{
{{Value: "Alice"}, {Value: "100"}},
{{Value: "Bob"}, {Value: "85"}},
}
if err := csvpputil.WriteYAML(os.Stdout, headers, records); err != nil {
log.Fatal(err)
}
Output: - name: Alice score: "100" - name: Bob score: "85"
Types ¶
type JSONArrayWriter ¶ added in v0.0.4
type JSONArrayWriter struct {
// contains filtered or unexported fields
}
JSONArrayWriter writes CSV++ records as a JSON array using streaming output. It uses jsontext.Encoder internally for efficient token-level writing.
Example ¶
headers := []*csvpp.ColumnHeader{
{Name: "name", Kind: csvpp.SimpleField},
{Name: "score", Kind: csvpp.SimpleField},
}
w := csvpputil.NewJSONArrayWriter(os.Stdout, headers, csvpputil.WithDeterministic(true))
if err := w.Write([]*csvpp.Field{{Value: "Alice"}, {Value: "100"}}); err != nil {
log.Fatal(err)
}
if err := w.Write([]*csvpp.Field{{Value: "Bob"}, {Value: "85"}}); err != nil {
log.Fatal(err)
}
if err := w.Close(); err != nil {
log.Fatal(err)
}
Output: [{"name":"Alice","score":"100"},{"name":"Bob","score":"85"}]
func NewJSONArrayWriter ¶ added in v0.0.4
func NewJSONArrayWriter(w io.Writer, headers []*csvpp.ColumnHeader, opts ...JSONArrayWriterOption) *JSONArrayWriter
NewJSONArrayWriter creates a new JSONArrayWriter that writes to w.
func (*JSONArrayWriter) Close ¶ added in v0.0.4
func (w *JSONArrayWriter) Close() error
Close finishes the JSON array by writing ']'. jsontext.Encoder auto-flushes, so no explicit Flush needed.
type JSONArrayWriterOption ¶ added in v0.0.4
type JSONArrayWriterOption func(*JSONArrayWriter)
JSONArrayWriterOption is a functional option for JSONArrayWriter.
func WithDeterministic
deprecated
func WithDeterministic(_ bool) JSONArrayWriterOption
WithDeterministic is kept for API compatibility but has no effect. Output order is always determined by the headers order.
Deprecated: This option is no longer needed as output order follows headers order.
type YAMLArrayWriter ¶ added in v0.0.4
type YAMLArrayWriter struct {
// contains filtered or unexported fields
}
YAMLArrayWriter writes CSV++ records as a YAML array. Due to YAML's structure (go-yaml doesn't support streaming array elements), records are buffered until Close.
Example ¶
headers := []*csvpp.ColumnHeader{
{Name: "name", Kind: csvpp.SimpleField},
{Name: "score", Kind: csvpp.SimpleField},
}
w := csvpputil.NewYAMLArrayWriter(os.Stdout, headers)
if err := w.Write([]*csvpp.Field{{Value: "Alice"}, {Value: "100"}}); err != nil {
log.Fatal(err)
}
if err := w.Write([]*csvpp.Field{{Value: "Bob"}, {Value: "85"}}); err != nil {
log.Fatal(err)
}
if err := w.Close(); err != nil {
log.Fatal(err)
}
Output: - name: Alice score: "100" - name: Bob score: "85"
func NewYAMLArrayWriter ¶ added in v0.0.4
func NewYAMLArrayWriter(w io.Writer, headers []*csvpp.ColumnHeader) *YAMLArrayWriter
NewYAMLArrayWriter creates a new YAMLArrayWriter that writes to w.
func (*YAMLArrayWriter) Close ¶ added in v0.0.4
func (w *YAMLArrayWriter) Close() error
Close writes all buffered records as a YAML array and closes the writer. go-yaml requires the complete array for proper YAML array output.
Source Files