Overview
Request parameters that correspond to file uploads in multipart requests are typed as io.Reader. The SDK provides flexible options for customizing file names and content types.
Default Behavior
The contents of the io.Reader will by default be sent as a multipart form part with:
- File name:
"anonymous_file"
- Content-Type:
"application/octet-stream"
The file name and content-type can be customized by implementing methods on the run-time type of io.Reader:
Name() string - for custom file nameContentType() string - for custom content type
os.File implements Name() string, so a file returned by os.Open will be sent with the file name on disk.
Using os.File
file, err := os.Open("document.pdf")
if err != nil {
panic(err)
}
defer file.Close()
// The file will be uploaded with the name "document.pdf"
response, err := client.Files.Upload(
context.TODO(),
FileUploadParams{
File: file,
},
)
Helper Function
We provide a helper gcore.File(reader io.Reader, filename string, contentType string) which can be used to wrap any io.Reader with the appropriate file name and content type.
Using gcore.File Helper
import (
"bytes"
"context"
"github.com/G-Core/gcore-go"
)
// Create a file from a byte buffer
data := []byte("file contents")
reader := bytes.NewReader(data)
// Wrap with custom metadata
file := gcore.File(reader, "custom-name.txt", "text/plain")
response, err := client.Files.Upload(
context.TODO(),
FileUploadParams{
File: file,
},
)
Examples
Upload from Memory
import "strings"
content := "Hello, World!"
reader := strings.NewReader(content)
file := gcore.File(reader, "greeting.txt", "text/plain")
response, err := client.Files.Upload(
context.TODO(),
FileUploadParams{
File: file,
},
)
Upload JSON Data
import (
"bytes"
"encoding/json"
)
data := map[string]interface{}{
"key": "value",
"items": []int{1, 2, 3},
}
jsonData, err := json.Marshal(data)
if err != nil {
panic(err)
}
reader := bytes.NewReader(jsonData)
file := gcore.File(reader, "data.json", "application/json")
response, err := client.Files.Upload(
context.TODO(),
FileUploadParams{
File: file,
},
)
Upload Binary Data
import "bytes"
// Binary data (e.g., image bytes)
binaryData := []byte{0x89, 0x50, 0x4E, 0x47, /* ... */}
reader := bytes.NewReader(binaryData)
file := gcore.File(reader, "image.png", "image/png")
response, err := client.Files.Upload(
context.TODO(),
FileUploadParams{
File: file,
},
)
The gcore.File helper accepts any io.Reader, making it flexible for various data sources including files, buffers, streams, and HTTP responses.
