distribution/registry/api/v2/urls.go

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package v2
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import (
"fmt"
"net"
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"net/http"
"net/url"
"strconv"
"strings"
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"github.com/docker/distribution/reference"
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"github.com/gorilla/mux"
)
// URLBuilder creates registry API urls from a single base endpoint. It can be
// used to create urls for use in a registry client or server.
//
// All urls will be created from the given base, including the api version.
// For example, if a root of "/foo/" is provided, urls generated will be fall
// under "/foo/v2/...". Most application will only provide a schema, host and
// port, such as "https://localhost:5000/".
type URLBuilder struct {
root *url.URL // url root (ie http://localhost/)
router *mux.Router
relative bool
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}
// NewURLBuilder creates a URLBuilder with provided root url object.
func NewURLBuilder(root *url.URL, relative bool) *URLBuilder {
return &URLBuilder{
root: root,
router: Router(),
relative: relative,
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}
}
// NewURLBuilderFromString workes identically to NewURLBuilder except it takes
// a string argument for the root, returning an error if it is not a valid
// url.
func NewURLBuilderFromString(root string, relative bool) (*URLBuilder, error) {
u, err := url.Parse(root)
if err != nil {
return nil, err
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}
return NewURLBuilder(u, relative), nil
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}
// NewURLBuilderFromRequest uses information from an *http.Request to
// construct the root url.
func NewURLBuilderFromRequest(r *http.Request, relative bool) *URLBuilder {
var scheme string
forwardedProto := r.Header.Get("X-Forwarded-Proto")
// TODO: log the error
forwardedHeader, _, _ := parseForwardedHeader(r.Header.Get("Forwarded"))
switch {
case len(forwardedProto) > 0:
scheme = forwardedProto
case len(forwardedHeader["proto"]) > 0:
scheme = forwardedHeader["proto"]
case r.TLS != nil:
scheme = "https"
case len(r.URL.Scheme) > 0:
scheme = r.URL.Scheme
default:
scheme = "http"
}
host := r.Host
if forwardedHost := r.Header.Get("X-Forwarded-Host"); len(forwardedHost) > 0 {
// According to the Apache mod_proxy docs, X-Forwarded-Host can be a
// comma-separated list of hosts, to which each proxy appends the
// requested host. We want to grab the first from this comma-separated
// list.
hosts := strings.SplitN(forwardedHost, ",", 2)
host = strings.TrimSpace(hosts[0])
} else if addr, exists := forwardedHeader["for"]; exists {
host = addr
} else if h, exists := forwardedHeader["host"]; exists {
host = h
}
portLessHost, port := host, ""
if !isIPv6Address(portLessHost) {
// with go 1.6, this would treat the last part of IPv6 address as a port
portLessHost, port, _ = net.SplitHostPort(host)
}
if forwardedPort := r.Header.Get("X-Forwarded-Port"); len(port) == 0 && len(forwardedPort) > 0 {
ports := strings.SplitN(forwardedPort, ",", 2)
forwardedPort = strings.TrimSpace(ports[0])
if _, err := strconv.ParseInt(forwardedPort, 10, 32); err == nil {
port = forwardedPort
}
}
if len(portLessHost) > 0 {
host = portLessHost
}
if len(port) > 0 {
// remove enclosing brackets of ipv6 address otherwise they will be duplicated
if len(host) > 1 && host[0] == '[' && host[len(host)-1] == ']' {
host = host[1 : len(host)-1]
}
// JoinHostPort properly encloses ipv6 addresses in square brackets
host = net.JoinHostPort(host, port)
} else if isIPv6Address(host) && host[0] != '[' {
// ipv6 needs to be enclosed in square brackets in urls
host = "[" + host + "]"
}
basePath := routeDescriptorsMap[RouteNameBase].Path
requestPath := r.URL.Path
index := strings.Index(requestPath, basePath)
u := &url.URL{
Scheme: scheme,
Host: host,
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}
if index > 0 {
// N.B. index+1 is important because we want to include the trailing /
u.Path = requestPath[0 : index+1]
}
return NewURLBuilder(u, relative)
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}
// BuildBaseURL constructs a base url for the API, typically just "/v2/".
func (ub *URLBuilder) BuildBaseURL() (string, error) {
route := ub.cloneRoute(RouteNameBase)
baseURL, err := route.URL()
if err != nil {
return "", err
}
return baseURL.String(), nil
}
// BuildCatalogURL constructs a url get a catalog of repositories
func (ub *URLBuilder) BuildCatalogURL(values ...url.Values) (string, error) {
route := ub.cloneRoute(RouteNameCatalog)
catalogURL, err := route.URL()
if err != nil {
return "", err
}
return appendValuesURL(catalogURL, values...).String(), nil
}
// BuildTagsURL constructs a url to list the tags in the named repository.
func (ub *URLBuilder) BuildTagsURL(name reference.Named) (string, error) {
route := ub.cloneRoute(RouteNameTags)
tagsURL, err := route.URL("name", name.Name())
if err != nil {
return "", err
}
return tagsURL.String(), nil
}
// BuildManifestURL constructs a url for the manifest identified by name and
// reference. The argument reference may be either a tag or digest.
func (ub *URLBuilder) BuildManifestURL(ref reference.Named) (string, error) {
route := ub.cloneRoute(RouteNameManifest)
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tagOrDigest := ""
switch v := ref.(type) {
case reference.Tagged:
tagOrDigest = v.Tag()
case reference.Digested:
tagOrDigest = v.Digest().String()
default:
return "", fmt.Errorf("reference must have a tag or digest")
}
manifestURL, err := route.URL("name", ref.Name(), "reference", tagOrDigest)
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if err != nil {
return "", err
}
return manifestURL.String(), nil
}
// BuildBlobURL constructs the url for the blob identified by name and dgst.
func (ub *URLBuilder) BuildBlobURL(ref reference.Canonical) (string, error) {
route := ub.cloneRoute(RouteNameBlob)
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layerURL, err := route.URL("name", ref.Name(), "digest", ref.Digest().String())
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if err != nil {
return "", err
}
return layerURL.String(), nil
}
// BuildBlobUploadURL constructs a url to begin a blob upload in the
// repository identified by name.
func (ub *URLBuilder) BuildBlobUploadURL(name reference.Named, values ...url.Values) (string, error) {
route := ub.cloneRoute(RouteNameBlobUpload)
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uploadURL, err := route.URL("name", name.Name())
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if err != nil {
return "", err
}
return appendValuesURL(uploadURL, values...).String(), nil
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}
// BuildBlobUploadChunkURL constructs a url for the upload identified by uuid,
// including any url values. This should generally not be used by clients, as
// this url is provided by server implementations during the blob upload
// process.
func (ub *URLBuilder) BuildBlobUploadChunkURL(name reference.Named, uuid string, values ...url.Values) (string, error) {
route := ub.cloneRoute(RouteNameBlobUploadChunk)
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uploadURL, err := route.URL("name", name.Name(), "uuid", uuid)
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if err != nil {
return "", err
}
return appendValuesURL(uploadURL, values...).String(), nil
}
// clondedRoute returns a clone of the named route from the router. Routes
// must be cloned to avoid modifying them during url generation.
func (ub *URLBuilder) cloneRoute(name string) clonedRoute {
route := new(mux.Route)
root := new(url.URL)
*route = *ub.router.GetRoute(name) // clone the route
*root = *ub.root
return clonedRoute{Route: route, root: root, relative: ub.relative}
}
type clonedRoute struct {
*mux.Route
root *url.URL
relative bool
}
func (cr clonedRoute) URL(pairs ...string) (*url.URL, error) {
routeURL, err := cr.Route.URL(pairs...)
if err != nil {
return nil, err
}
if cr.relative {
return routeURL, nil
}
if routeURL.Scheme == "" && routeURL.User == nil && routeURL.Host == "" {
routeURL.Path = routeURL.Path[1:]
}
url := cr.root.ResolveReference(routeURL)
url.Scheme = cr.root.Scheme
return url, nil
}
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// appendValuesURL appends the parameters to the url.
func appendValuesURL(u *url.URL, values ...url.Values) *url.URL {
merged := u.Query()
for _, v := range values {
for k, vv := range v {
merged[k] = append(merged[k], vv...)
}
}
u.RawQuery = merged.Encode()
return u
}
// appendValues appends the parameters to the url. Panics if the string is not
// a url.
func appendValues(u string, values ...url.Values) string {
up, err := url.Parse(u)
if err != nil {
panic(err) // should never happen
}
return appendValuesURL(up, values...).String()
}
// isIPv6Address returns true if given string is a valid IPv6 address. No port is allowed. The address may be
// enclosed in square brackets.
func isIPv6Address(host string) bool {
if len(host) > 1 && host[0] == '[' && host[len(host)-1] == ']' {
host = host[1 : len(host)-1]
}
// The IPv6 scoped addressing zone identifier starts after the last percent sign.
if i := strings.LastIndexByte(host, '%'); i > 0 {
host = host[:i]
}
ip := net.ParseIP(host)
if ip == nil {
return false
}
if ip.To16() == nil {
return false
}
if ip.To4() == nil {
return true
}
// dot can be present in ipv4-mapped address, it needs to come after a colon though
i := strings.IndexAny(host, ":.")
return i >= 0 && host[i] == ':'
}