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package gophercloud
import (
"bytes"
"encoding/json"
"fmt"
"io"
"io/ioutil"
"net/http"
"strings"
)
// DefaultUserAgent is the default User-Agent string set in the request header.
const DefaultUserAgent = "gophercloud/1.0.0"
// UserAgent represents a User-Agent header.
type UserAgent struct {
// prepend is the slice of User-Agent strings to prepend to DefaultUserAgent.
// All the strings to prepend are accumulated and prepended in the Join method.
prepend []string
}
// Prepend prepends a user-defined string to the default User-Agent string. Users
// may pass in one or more strings to prepend.
func (ua *UserAgent) Prepend(s ...string) {
ua.prepend = append(s, ua.prepend...)
}
// Join concatenates all the user-defined User-Agend strings with the default
// Gophercloud User-Agent string.
func (ua *UserAgent) Join() string {
uaSlice := append(ua.prepend, DefaultUserAgent)
return strings.Join(uaSlice, " ")
}
// ProviderClient stores details that are required to interact with any
// services within a specific provider's API.
//
// Generally, you acquire a ProviderClient by calling the NewClient method in
// the appropriate provider's child package, providing whatever authentication
// credentials are required.
type ProviderClient struct {
// IdentityBase is the base URL used for a particular provider's identity
// service - it will be used when issuing authenticatation requests. It
// should point to the root resource of the identity service, not a specific
// identity version.
IdentityBase string
// IdentityEndpoint is the identity endpoint. This may be a specific version
// of the identity service. If this is the case, this endpoint is used rather
// than querying versions first.
IdentityEndpoint string
// TokenID is the ID of the most recently issued valid token.
TokenID string
// EndpointLocator describes how this provider discovers the endpoints for
// its constituent services.
EndpointLocator EndpointLocator
// HTTPClient allows users to interject arbitrary http, https, or other transit behaviors.
HTTPClient http.Client
// UserAgent represents the User-Agent header in the HTTP request.
UserAgent UserAgent
// ReauthFunc is the function used to re-authenticate the user if the request
// fails with a 401 HTTP response code. This a needed because there may be multiple
// authentication functions for different Identity service versions.
ReauthFunc func() error
}
// AuthenticatedHeaders returns a map of HTTP headers that are common for all
// authenticated service requests.
func (client *ProviderClient) AuthenticatedHeaders() map[string]string {
if client.TokenID == "" {
return map[string]string{}
}
return map[string]string{"X-Auth-Token": client.TokenID}
}
// RequestOpts customizes the behavior of the provider.Request() method.
type RequestOpts struct {
// JSONBody, if provided, will be encoded as JSON and used as the body of the HTTP request. The
// content type of the request will default to "application/json" unless overridden by MoreHeaders.
// It's an error to specify both a JSONBody and a RawBody.
JSONBody interface{}
// RawBody contains an io.ReadSeeker that will be consumed by the request directly. No content-type
// will be set unless one is provided explicitly by MoreHeaders.
RawBody io.ReadSeeker
// JSONResponse, if provided, will be populated with the contents of the response body parsed as
// JSON.
JSONResponse interface{}
// OkCodes contains a list of numeric HTTP status codes that should be interpreted as success. If
// the response has a different code, an error will be returned.
OkCodes []int
// MoreHeaders specifies additional HTTP headers to be provide on the request. If a header is
// provided with a blank value (""), that header will be *omitted* instead: use this to suppress
// the default Accept header or an inferred Content-Type, for example.
MoreHeaders map[string]string
}
func (opts *RequestOpts) setBody(body interface{}) {
if v, ok := (body).(io.ReadSeeker); ok {
opts.RawBody = v
} else if body != nil {
opts.JSONBody = body
}
}
// UnexpectedResponseCodeError is returned by the Request method when a response code other than
// those listed in OkCodes is encountered.
type UnexpectedResponseCodeError struct {
URL string
Method string
Expected []int
Actual int
Body []byte
}
func (err *UnexpectedResponseCodeError) Error() string {
return fmt.Sprintf(
"Expected HTTP response code %v when accessing [%s %s], but got %d instead\n%s",
err.Expected, err.Method, err.URL, err.Actual, err.Body,
)
}
var applicationJSON = "application/json"
// Request performs an HTTP request using the ProviderClient's current HTTPClient. An authentication
// header will automatically be provided.
func (client *ProviderClient) Request(method, url string, options RequestOpts) (*http.Response, error) {
var body io.ReadSeeker
var contentType *string
// Derive the content body by either encoding an arbitrary object as JSON, or by taking a provided
// io.ReadSeeker as-is. Default the content-type to application/json.
if options.JSONBody != nil {
if options.RawBody != nil {
panic("Please provide only one of JSONBody or RawBody to gophercloud.Request().")
}
rendered, err := json.Marshal(options.JSONBody)
if err != nil {
return nil, err
}
body = bytes.NewReader(rendered)
contentType = &applicationJSON
}
if options.RawBody != nil {
body = options.RawBody
}
// Construct the http.Request.
req, err := http.NewRequest(method, url, body)
if err != nil {
return nil, err
}
// Populate the request headers. Apply options.MoreHeaders last, to give the caller the chance to
// modify or omit any header.
if contentType != nil {
req.Header.Set("Content-Type", *contentType)
}
req.Header.Set("Accept", applicationJSON)
for k, v := range client.AuthenticatedHeaders() {
req.Header.Add(k, v)
}
// Set the User-Agent header
req.Header.Set("User-Agent", client.UserAgent.Join())
if options.MoreHeaders != nil {
for k, v := range options.MoreHeaders {
if v != "" {
req.Header.Set(k, v)
} else {
req.Header.Del(k)
}
}
}
// Set connection parameter to close the connection immediately when we've got the response
req.Close = true
// Issue the request.
resp, err := client.HTTPClient.Do(req)
if err != nil {
return nil, err
}
if resp.StatusCode == http.StatusUnauthorized {
if client.ReauthFunc != nil {
err = client.ReauthFunc()
if err != nil {
return nil, fmt.Errorf("Error trying to re-authenticate: %s", err)
}
if options.RawBody != nil {
options.RawBody.Seek(0, 0)
}
resp.Body.Close()
resp, err = client.Request(method, url, options)
if err != nil {
return nil, fmt.Errorf("Successfully re-authenticated, but got error executing request: %s", err)
}
return resp, nil
}
}
// Allow default OkCodes if none explicitly set
if options.OkCodes == nil {
options.OkCodes = defaultOkCodes(method)
}
// Validate the HTTP response status.
var ok bool
for _, code := range options.OkCodes {
if resp.StatusCode == code {
ok = true
break
}
}
if !ok {
body, _ := ioutil.ReadAll(resp.Body)
resp.Body.Close()
return resp, &UnexpectedResponseCodeError{
URL: url,
Method: method,
Expected: options.OkCodes,
Actual: resp.StatusCode,
Body: body,
}
}
// Parse the response body as JSON, if requested to do so.
if options.JSONResponse != nil {
defer resp.Body.Close()
if err := json.NewDecoder(resp.Body).Decode(options.JSONResponse); err != nil {
return nil, err
}
}
return resp, nil
}
func defaultOkCodes(method string) []int {
switch {
case method == "GET":
return []int{200}
case method == "POST":
return []int{201, 202}
case method == "PUT":
return []int{201, 202}
case method == "PATCH":
return []int{200, 204}
case method == "DELETE":
return []int{202, 204}
}
return []int{}
}
func (client *ProviderClient) Get(url string, JSONResponse *interface{}, opts *RequestOpts) (*http.Response, error) {
if opts == nil {
opts = &RequestOpts{}
}
if JSONResponse != nil {
opts.JSONResponse = JSONResponse
}
return client.Request("GET", url, *opts)
}
func (client *ProviderClient) Post(url string, body interface{}, JSONResponse *interface{}, opts *RequestOpts) (*http.Response, error) {
if opts == nil {
opts = &RequestOpts{}
}
opts.setBody(body)
if JSONResponse != nil {
opts.JSONResponse = JSONResponse
}
return client.Request("POST", url, *opts)
}
func (client *ProviderClient) Put(url string, body interface{}, JSONResponse *interface{}, opts *RequestOpts) (*http.Response, error) {
if opts == nil {
opts = &RequestOpts{}
}
opts.setBody(body)
if JSONResponse != nil {
opts.JSONResponse = JSONResponse
}
return client.Request("PUT", url, *opts)
}
func (client *ProviderClient) Patch(url string, JSONBody interface{}, JSONResponse *interface{}, opts *RequestOpts) (*http.Response, error) {
if opts == nil {
opts = &RequestOpts{}
}
if v, ok := (JSONBody).(io.ReadSeeker); ok {
opts.RawBody = v
} else if JSONBody != nil {
opts.JSONBody = JSONBody
}
if JSONResponse != nil {
opts.JSONResponse = JSONResponse
}
return client.Request("PATCH", url, *opts)
}
func (client *ProviderClient) Delete(url string, opts *RequestOpts) (*http.Response, error) {
if opts == nil {
opts = &RequestOpts{}
}
return client.Request("DELETE", url, *opts)
}