Add RunWithOptions method that supports returning file output as io.ReadCloser (#77)

* Add RunWithOptions method that supports returning file output as bytes

* Return io.ReadCloser instead of []byte

* Add test coverage for RunWithOptions

* Return custom FileOutput type that implements io.ReadCloser and provides URL

Author: mattt

client_test.go

@@ -1475,6 +1475,79 @@ func TestAutomaticallyRetryPostRequests(t *testing.T) {
 	assert.ErrorContains(t, err, http.StatusText(http.StatusInternalServerError))
 }
 
+func TestRunWithOptions(t *testing.T) {
+	var mockServer *httptest.Server
+	mockServer = httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		switch r.URL.Path {
+		case "/predictions":
+			assert.Equal(t, http.MethodPost, r.Method)
+			prediction := replicate.Prediction{
+				ID:      "gtsllfynndufawqhdngldkdrkq",
+				Version: "5c7d5dc6dd8bf75c1acaa8565735e7986bc5b66206b55cca93cb72c9bf15ccaa",
+				Status:  replicate.Starting,
+			}
+			json.NewEncoder(w).Encode(prediction)
+		case "/predictions/gtsllfynndufawqhdngldkdrkq":
+			assert.Equal(t, http.MethodGet, r.Method)
+			prediction := replicate.Prediction{
+				ID:      "gtsllfynndufawqhdngldkdrkq",
+				Version: "5c7d5dc6dd8bf75c1acaa8565735e7986bc5b66206b55cca93cb72c9bf15ccaa",
+				Status:  replicate.Succeeded,
+				Output: map[string]interface{}{
+					"image": mockServer.URL + "/output.png",
+					"text":  "Hello, world!",
+				},
+			}
+			json.NewEncoder(w).Encode(prediction)
+		case "/output.png":
+			w.Header().Set("Content-Type", "image/png")
+			w.Write([]byte("mock image data"))
+		default:
+			t.Fatalf("Unexpected request to %s", r.URL.Path)
+		}
+	}))
+	defer mockServer.Close()
+
+	client, err := replicate.NewClient(
+		replicate.WithToken("test-token"),
+		replicate.WithBaseURL(mockServer.URL),
+	)
+	require.NoError(t, err)
+
+	ctx := context.Background()
+	input := replicate.PredictionInput{"prompt": "A test image"}
+
+	// Test with WithFileOutput option
+	output, err := client.RunWithOptions(ctx, "owner/model:5c7d5dc6dd8bf75c1acaa8565735e7986bc5b66206b55cca93cb72c9bf15ccaa", input, nil, replicate.WithFileOutput())
+
+	require.NoError(t, err)
+	assert.NotNil(t, output)
+
+	// Check if the image output is transformed to io.ReadCloser
+	imageOutput, ok := output.(map[string]interface{})["image"].(io.ReadCloser)
+	require.True(t, ok, "Expected image output to be io.ReadCloser")
+
+	imageData, err := io.ReadAll(imageOutput)
+	require.NoError(t, err)
+	assert.Equal(t, []byte("mock image data"), imageData)
+
+	// Check if the text output remains unchanged
+	textOutput, ok := output.(map[string]interface{})["text"].(string)
+	require.True(t, ok, "Expected text output to be string")
+	assert.Equal(t, "Hello, world!", textOutput)
+
+	// Test without WithFileOutput option
+	outputWithoutFileOption, err := client.RunWithOptions(ctx, "owner/model:5c7d5dc6dd8bf75c1acaa8565735e7986bc5b66206b55cca93cb72c9bf15ccaa", input, nil)
+
+	require.NoError(t, err)
+	assert.NotNil(t, outputWithoutFileOption)
+
+	// Check if the image output remains a URL string
+	imageOutputURL, ok := outputWithoutFileOption.(map[string]interface{})["image"].(string)
+	require.True(t, ok, "Expected image output to be string")
+	assert.Equal(t, mockServer.URL+"/output.png", imageOutputURL)
+}
+
 func TestStream(t *testing.T) {
 	tokens := []string{"Alpha", "Bravo", "Charlie", "Delta", "Echo"}
 

run.go

@@ -1,11 +1,45 @@
 package replicate
 
 import (
+	"bytes"
 	"context"
+	"encoding/base64"
 	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"strings"
 )
 
-func (r *Client) Run(ctx context.Context, identifier string, input PredictionInput, webhook *Webhook) (PredictionOutput, error) {
+// RunOption is a function that modifies RunOptions
+type RunOption func(*runOptions)
+
+// runOptions represents options for running a model
+type runOptions struct {
+	useFileOutput bool
+}
+
+// FileOutput is a custom type that implements io.ReadCloser and includes a URL field
+type FileOutput struct {
+	io.ReadCloser
+	URL string
+}
+
+// WithFileOutput sets the UseFileOutput option to true
+func WithFileOutput() RunOption {
+	return func(o *runOptions) {
+		o.useFileOutput = true
+	}
+}
+
+// RunWithOptions runs a model with specified options
+func (r *Client) RunWithOptions(ctx context.Context, identifier string, input PredictionInput, webhook *Webhook, opts ...RunOption) (PredictionOutput, error) {
+	options := runOptions{}
+	for _, opt := range opts {
+		opt(&options)
+	}
+
 	id, err := ParseIdentifier(identifier)
 	if err != nil {
 		return nil, err
@@ -29,5 +63,96 @@ func (r *Client) Run(ctx context.Context, identifier string, input PredictionInp
 		return nil, &ModelError{Prediction: prediction}
 	}
 
+	if options.useFileOutput {
+		return transformOutput(ctx, prediction.Output, r)
+	}
+
 	return prediction.Output, nil
 }
+
+// Run runs a model and returns the output
+func (r *Client) Run(ctx context.Context, identifier string, input PredictionInput, webhook *Webhook) (PredictionOutput, error) {
+	return r.RunWithOptions(ctx, identifier, input, webhook)
+}
+
+func transformOutput(ctx context.Context, value interface{}, client *Client) (interface{}, error) {
+	var err error
+	switch v := value.(type) {
+	case map[string]interface{}:
+		for k, val := range v {
+			v[k], err = transformOutput(ctx, val, client)
+			if err != nil {
+				return nil, err
+			}
+		}
+		return v, nil
+	case []interface{}:
+		for i, val := range v {
+			v[i], err = transformOutput(ctx, val, client)
+			if err != nil {
+				return nil, err
+			}
+		}
+		return v, nil
+	case string:
+		if strings.HasPrefix(v, "data:") {
+			return readDataURI(v)
+		}
+		if strings.HasPrefix(v, "https:") || strings.HasPrefix(v, "http:") {
+			return readHTTP(ctx, v, client)
+		}
+		return v, nil
+	}
+	return value, nil
+}
+
+func readDataURI(uri string) (*FileOutput, error) {
+	u, err := url.Parse(uri)
+	if err != nil {
+		return nil, err
+	}
+	if u.Scheme != "data" {
+		return nil, errors.New("not a data URI")
+	}
+	mediatype, data, found := strings.Cut(u.Opaque, ",")
+	if !found {
+		return nil, errors.New("invalid data URI format")
+	}
+	var reader io.Reader
+	if strings.HasSuffix(mediatype, ";base64") {
+		decoded, err := base64.StdEncoding.DecodeString(data)
+		if err != nil {
+			return nil, err
+		}
+		reader = bytes.NewReader(decoded)
+	} else {
+		reader = strings.NewReader(data)
+	}
+	return &FileOutput{
+		ReadCloser: io.NopCloser(reader),
+		URL:        uri,
+	}, nil
+}
+
+func readHTTP(ctx context.Context, url string, client *Client) (*FileOutput, error) {
+	req, err := http.NewRequestWithContext(ctx, "GET", url, nil)
+	if err != nil {
+		return nil, err
+	}
+	resp, err := client.c.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	if resp == nil || resp.Body == nil {
+		return nil, errors.New("HTTP request failed to get a response")
+	}
+	if resp.StatusCode != http.StatusOK {
+		resp.Body.Close()
+		return nil, fmt.Errorf("HTTP request failed with status code %d", resp.StatusCode)
+	}
+
+	return &FileOutput{
+		ReadCloser: resp.Body,
+		URL:        url,
+	}, nil
+}