Glazed provides two new field types file and fileList that allow passing file paths which will be automatically loaded and parsed.

The FileData structure

File fields are parsed into a single or a list of FileData structures which can then be accessed from within a template.

package fields

const (
	Unknown FileType = "Unknown"
	JSON    FileType = "JSON"
	YAML    FileType = "YAML"
	CSV     FileType = "CSV"
	TEXT    FileType = "TEXT"
)

type FileData struct {
	Content          string
	ParsedContent    interface{}
	ParseError       error
	RawContent       []byte
	StringContent    string
	IsList           bool
	IsObject         bool
	BaseName         string
	Extension        string
	FileType         FileType
	Path             string
	RelativePath     string
	AbsolutePath     string
	Size             int64
	LastModifiedTime time.Time
	Permissions      os.FileMode
	IsDirectory      bool
}

Using FileData in Templates

The FileData structure returned by the file and fileList fields can be easily used inside templates.

For example, to loop through a list of files:

{{ range .input_files }}

Filename: {{ .Name }}
Content: {{ .Content }}

{{ end }}

Since Glazed parses the file content based on the extension, you can access nested fields of parsed structures:

{{ range .json_files }}

Name: {{ .Name }}  
User: {{ .ParsedContent.user.name }}

{{ end }}

This will print the name field from the user object parsed from the JSON content.

Similar direct access is possible for YAML, CSV and other parsed file types.

This makes it very easy to build templates that can ingest a variety of file types.

The file Type

The file field type allows passing a single file path, which will be read and parsed into a FileData structure.

For example:

  - name: file
    type: file
    help: Input file for generating JSON schema
    required: true

Then running

command --file filename

This will read the content of <filename>, attempt to parse it based on the file extension, and return a FileData object that contains:

• The raw content as bytes
• The parsed content (e.g. JSON/YAML/CSV parsed into native Go structures)
• File metadata like name, path, size etc.

The command implementation can then easily access both the raw bytes/string content as well as the parsed representation.

The fileList Field

Similarly, fileList allows passing multiple file paths, which will be turned into a list of FileData objects:

For example:

  - name: input_files
    type: fileList
    help: Input files for generating JSON schema
    required: true

Then running:

command --input-files <file1>,<file2> ...

This makes it easy to load and process multiple files in a single command.

The command receives a slice of FileData instances to work with.