sketch out how requests could work

1 files changed, 161 insertions, 0 deletions

diff --git a/request.go b/request.go
new file mode 100644
index 0000000..c6bef7b
--- /dev/null
+++ b/request.go
@@ -0,0 +1,161 @@
+/******************************************************************************
+*
+*  Copyright 2018 Stefan Majewsky <majewsky@gmx.net>
+*
+*  Licensed under the Apache License, Version 2.0 (the "License");
+*  you may not use this file except in compliance with the License.
+*  You may obtain a copy of the License at
+*
+*      http://www.apache.org/licenses/LICENSE-2.0
+*
+*  Unless required by applicable law or agreed to in writing, software
+*  distributed under the License is distributed on an "AS IS" BASIS,
+*  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+*  See the License for the specific language governing permissions and
+*  limitations under the License.
+*
+******************************************************************************/
+
+package schwift
+
+import (
+	"io"
+	"io/ioutil"
+	"net/http"
+	urlmodule "net/url"
+	"strings"
+
+	"github.com/gophercloud/gophercloud"
+)
+
+var okCodes []int
+
+func init() {
+	//prepare input for gophercloud.RequestOpts.OkCodes such that gophercloud's
+	//error handling is fused
+	for code := 100; code < 600; code++ {
+		//as an exception, 401s are handled by Gophercloud because we want to use its
+		//internal token renewal logic
+		if code != 401 {
+			okCodes = append(okCodes, code)
+		}
+	}
+}
+
+//Request contains the parameters that can be set in a request to the Swift API.
+type Request struct {
+	Method            string //"GET", "HEAD", "PUT", "POST" or "DELETE"
+	ContainerName     string //empty for requests on accounts
+	ObjectName        string //empty for requests on accounts/containers
+	AdditionalHeaders map[string]string
+	//ExpectStatusCodes can be left empty to disable this check, otherwise
+	//schwift.UnexpectedStatusCodeError may be returned.
+	ExpectStatusCodes []int
+}
+
+//URL returns the full URL for this request.
+func (r Request) URL(client *gophercloud.ServiceClient) (string, error) {
+	url, err := urlmodule.Parse(client.Endpoint)
+	if err != nil {
+		return "", err
+	}
+	if !strings.HasSuffix(url.Path, "/") {
+		url.Path += "/"
+	}
+
+	if r.ContainerName == "" {
+		if r.ObjectName != "" {
+			return "", ErrNoContainerName
+		}
+	} else {
+		if strings.Contains(r.ContainerName, "/") {
+			return "", ErrMalformedContainerName
+		}
+		url.Path += r.ContainerName + "/" + r.ObjectName
+	}
+
+	return url.String(), nil
+}
+
+//Do executes this request on the given service client.
+func (r Request) Do(client *gophercloud.ServiceClient) (*http.Response, error) {
+	return r.do(client, false)
+}
+
+func (r Request) do(client *gophercloud.ServiceClient, afterReauth bool) (*http.Response, error) {
+	//build URL
+	url, err := r.URL(client)
+	if err != nil {
+		return nil, err
+	}
+
+	//override gophercloud's error handling
+	opts := &gophercloud.RequestOpts{OkCodes: okCodes}
+
+	//override gophercloud's default headers
+	opts.MoreHeaders = map[string]string{
+		"Accept":       "",
+		"Content-Type": "",
+	}
+	for key, value := range r.AdditionalHeaders {
+		opts.MoreHeaders[key] = value
+	}
+
+	resp, err := client.ProviderClient.Request(r.Method, url, opts)
+	if err != nil {
+		return resp, err
+	}
+
+	//return success if error code matches expectation
+	if len(r.ExpectStatusCodes) == 0 {
+		//check disabled -> return response unaltered
+		return resp, nil
+	}
+	for _, code := range r.ExpectStatusCodes {
+		if code == resp.StatusCode {
+			return resp, nil
+		}
+	}
+
+	//since we override gophercloud's error handling, we need to handle token
+	//expiry ourselves
+	if resp.StatusCode == http.StatusUnauthorized && !afterReauth {
+		err := drainResponseBody(resp)
+		if err != nil {
+			return nil, err
+		}
+		err = client.Reauthenticate(resp.Request.Header.Get("X-Auth-Token"))
+		if err != nil {
+			return nil, err
+		}
+		//restart request with new token
+		return r.do(client, true)
+	}
+
+	//other unexpected status code -> generate UnexpectedStatusCodeError
+	buf, err := collectResponseBody(resp)
+	if err != nil {
+		return nil, err
+	}
+	return nil, UnexpectedStatusCodeError{
+		ExpectedStatusCodes: r.ExpectStatusCodes,
+		ActualResponse:      resp,
+		ResponseBody:        buf,
+	}
+}
+
+func drainResponseBody(r *http.Response) error {
+	_, err := io.Copy(ioutil.Discard, r.Body)
+	if err != nil {
+		return err
+	}
+	return r.Body.Close()
+}
+
+func collectResponseBody(r *http.Response) ([]byte, error) {
+	buf, err := ioutil.ReadAll(r.Body)
+	if err != nil {
+		return nil, err
+	}
+	return buf, r.Body.Close()
+}