姚章浩
81 lines
2.7 KiB
Go
81 lines
2.7 KiB
Go
package outboundimage
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import (
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"context"
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"errors"
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"fmt"
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"io"
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"net/http"
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"net/url"
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"strconv"
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"strings"
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"time"
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)
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type WeKnoraFetcher struct {
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baseURL *url.URL
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apiKey string
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client *http.Client
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maxBytes int64
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}
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func NewWeKnoraFetcher(baseURL, apiKey string, client *http.Client, maxBytes int64) (*WeKnoraFetcher, error) {
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parsed, err := url.Parse(strings.TrimRight(strings.TrimSpace(baseURL), "/"))
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if err != nil || parsed.Scheme == "" || parsed.Host == "" {
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return nil, errors.New("outbound image: invalid WeKnora base URL")
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}
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if strings.TrimSpace(apiKey) == "" {
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return nil, errors.New("outbound image: WeKnora API key is required")
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}
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if maxBytes <= 0 {
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return nil, errors.New("outbound image: positive max bytes is required")
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}
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if client == nil {
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client = &http.Client{Timeout: 30 * time.Second}
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}
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return &WeKnoraFetcher{baseURL: parsed, apiKey: apiKey, client: client, maxBytes: maxBytes}, nil
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}
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func (f *WeKnoraFetcher) Fetch(ctx context.Context, reference string) ([]byte, string, error) {
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if !strings.HasPrefix(reference, "resource://") || !resourceMarkdownImageRE.MatchString("![]("+reference+")") {
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return nil, "", errors.New("outbound image: unsupported resource reference")
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}
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u := *f.baseURL
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u.Path = "/files"
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u.RawPath = ""
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query := u.Query()
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query.Set("file_path", reference)
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u.RawQuery = query.Encode()
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req, err := http.NewRequestWithContext(ctx, http.MethodGet, u.String(), nil)
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if err != nil {
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return nil, "", errors.New("outbound image: create WeKnora request failed")
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}
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req.Header.Set("X-API-Key", f.apiKey)
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resp, err := f.client.Do(req)
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if err != nil {
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return nil, "", fmt.Errorf("outbound image: WeKnora request failed: %w", err)
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}
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defer resp.Body.Close()
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if resp.StatusCode < 200 || resp.StatusCode >= 300 {
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_, _ = io.Copy(io.Discard, io.LimitReader(resp.Body, 4096))
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return nil, "", fmt.Errorf("outbound image: WeKnora HTTP %d", resp.StatusCode)
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}
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contentType := strings.TrimSpace(strings.Split(resp.Header.Get("Content-Type"), ";")[0])
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if !strings.HasPrefix(contentType, "image/") {
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return nil, "", errors.New("outbound image: WeKnora response is not an image")
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}
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if length := strings.TrimSpace(resp.Header.Get("Content-Length")); length != "" {
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if n, convErr := strconv.ParseInt(length, 10, 64); convErr == nil && n > f.maxBytes {
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return nil, "", errors.New("outbound image: WeKnora image exceeds size limit")
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}
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}
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data, err := io.ReadAll(io.LimitReader(resp.Body, f.maxBytes+1))
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if err != nil {
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return nil, "", errors.New("outbound image: read WeKnora response failed")
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}
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if int64(len(data)) == 0 || int64(len(data)) > f.maxBytes {
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return nil, "", errors.New("outbound image: WeKnora image exceeds size limit")
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}
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return data, contentType, nil
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}
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