Golang distribution.ManifestMediaTypes函數代碼示例

// Get issues a HEAD request for a Manifest against its named endpoint in order
// to construct a descriptor for the tag.  If the registry doesn't support HEADing
// a manifest, fallback to GET.
func (t *tags) Get(ctx context.Context, tag string) (distribution.Descriptor, error) {
	ref, err := reference.WithTag(t.name, tag)
	if err != nil {
		return distribution.Descriptor{}, err
	}
	u, err := t.ub.BuildManifestURL(ref)
	if err != nil {
		return distribution.Descriptor{}, err
	}

	req, err := http.NewRequest("HEAD", u, nil)
	if err != nil {
		return distribution.Descriptor{}, err
	}

	for _, t := range distribution.ManifestMediaTypes() {
		req.Header.Add("Accept", t)
	}

	var attempts int
	resp, err := t.client.Do(req)
check:
	if err != nil {
		return distribution.Descriptor{}, err
	}
	defer resp.Body.Close()

	switch {
	case resp.StatusCode >= 200 && resp.StatusCode < 400:
		return descriptorFromResponse(resp)
	case resp.StatusCode == http.StatusMethodNotAllowed:
		req, err = http.NewRequest("GET", u, nil)
		if err != nil {
			return distribution.Descriptor{}, err
		}

		for _, t := range distribution.ManifestMediaTypes() {
			req.Header.Add("Accept", t)
		}

		resp, err = t.client.Do(req)
		attempts++
		if attempts > 1 {
			return distribution.Descriptor{}, err
		}
		goto check
	default:
		return distribution.Descriptor{}, HandleErrorResponse(resp)
	}
}

// Get issues a HEAD request for a Manifest against its named endpoint in order
// to construct a descriptor for the tag.  If the registry doesn't support HEADing
// a manifest, fallback to GET.
func (t *tags) Get(ctx context.Context, tag string) (distribution.Descriptor, error) {
	ref, err := reference.WithTag(t.name, tag)
	if err != nil {
		return distribution.Descriptor{}, err
	}
	u, err := t.ub.BuildManifestURL(ref)
	if err != nil {
		return distribution.Descriptor{}, err
	}

	newRequest := func(method string) (*http.Response, error) {
		req, err := http.NewRequest(method, u, nil)
		if err != nil {
			return nil, err
		}

		for _, t := range distribution.ManifestMediaTypes() {
			req.Header.Add("Accept", t)
		}
		resp, err := t.client.Do(req)
		return resp, err
	}

	resp, err := newRequest("HEAD")
	if err != nil {
		return distribution.Descriptor{}, err
	}
	defer resp.Body.Close()

	switch {
	case resp.StatusCode >= 200 && resp.StatusCode < 400:
		return descriptorFromResponse(resp)
	default:
		// if the response is an error - there will be no body to decode.
		// Issue a GET request:
		//   - for data from a server that does not handle HEAD
		//   - to get error details in case of a failure
		resp, err = newRequest("GET")
		if err != nil {
			return distribution.Descriptor{}, err
		}
		defer resp.Body.Close()

		if resp.StatusCode >= 200 && resp.StatusCode < 400 {
			return descriptorFromResponse(resp)
		}
		return distribution.Descriptor{}, HandleErrorResponse(resp)
	}
}

func (r *registry) getRequest(u, etag string) (req *http.Request, err error) {
	req, err = http.NewRequest("GET", u, nil)
	if err != nil {
		return nil, err
	}

	for _, t := range distribution.ManifestMediaTypes() {
		req.Header.Add("Accept", t)
	}

	if etag != "" {
		req.Header.Set("If-None-Match", etag)
	}
	return req, nil
}

func (ms *manifests) Get(ctx context.Context, dgst digest.Digest, options ...distribution.ManifestServiceOption) (distribution.Manifest, error) {

	var tag string
	for _, option := range options {
		if opt, ok := option.(withTagOption); ok {
			tag = opt.tag
		} else {
			err := option.Apply(ms)
			if err != nil {
				return nil, err
			}
		}
	}

	var ref string
	if tag != "" {
		ref = tag
	} else {
		ref = dgst.String()
	}

	u, err := ms.ub.BuildManifestURL(ms.name, ref)
	if err != nil {
		return nil, err
	}

	req, err := http.NewRequest("GET", u, nil)
	if err != nil {
		return nil, err
	}

	for _, t := range distribution.ManifestMediaTypes() {
		req.Header.Add("Accept", t)
	}

	if _, ok := ms.etags[ref]; ok {
		req.Header.Set("If-None-Match", ms.etags[ref])
	}

	resp, err := ms.client.Do(req)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()
	if resp.StatusCode == http.StatusNotModified {
		return nil, distribution.ErrManifestNotModified
	} else if SuccessStatus(resp.StatusCode) {
		mt := resp.Header.Get("Content-Type")
		body, err := ioutil.ReadAll(resp.Body)

		if err != nil {
			return nil, err
		}
		m, _, err := distribution.UnmarshalManifest(mt, body)
		if err != nil {
			return nil, err
		}
		return m, nil
	}
	return nil, HandleErrorResponse(resp)
}