provider_client.go - debian/gophercloud - Gitiles

 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/v1.0"

 // 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.Reader that will be consumed by the request directly. No content-type
 	// will be set unless one is provided explicitly by MoreHeaders.
 	RawBody io.Reader

 	// 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
 }

 // 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.Reader
 	var contentType *string

 	// Derive the content body by either encoding an arbitrary object as JSON, or by taking a provided
 	// io.Reader 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)
 			}
 		}
 	}

 	// 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)
 			}
 			resp, err = client.Request(method, url, options)
 			if err != nil {
 				return nil, fmt.Errorf("Successfully re-authenticated, but got error executing request: %s", err)
 			}
 		}
 	}

 	// Validate the response code, if requested to do so.
 	if options.OkCodes != nil {
 		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()
 		json.NewDecoder(resp.Body).Decode(options.JSONResponse)
 	}

 	return resp, nil
 }
	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/v1.0"

	// 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.Reader that will be consumed by the request directly. No content-type
	// will be set unless one is provided explicitly by MoreHeaders.
	RawBody io.Reader

	// 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
	}

	// 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.Reader
	var contentType *string

	// Derive the content body by either encoding an arbitrary object as JSON, or by taking a provided
	// io.Reader 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)
	}
	}
	}

	// 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)
	}
	resp, err = client.Request(method, url, options)
	if err != nil {
	return nil, fmt.Errorf("Successfully re-authenticated, but got error executing request: %s", err)
	}
	}
	}

	// Validate the response code, if requested to do so.
	if options.OkCodes != nil {
	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()
	json.NewDecoder(resp.Body).Decode(options.JSONResponse)
	}

	return resp, nil
	}