package storage
import (
"encoding/xml"
"fmt"
"net/http"
"net/url"
"strconv"
"strings"
)
const (
// casing is per Golang's http.Header canonicalizing the header names.
approximateMessagesCountHeader = "X-Ms-Approximate-Messages-Count"
userDefinedMetadataHeaderPrefix = "X-Ms-Meta-"
)
// QueueServiceClient contains operations for Microsoft Azure Queue Storage
// Service.
type QueueServiceClient struct {
client Client
}
func pathForQueue(queue string) string { return fmt.Sprintf("/%s", queue) }
func pathForQueueMessages(queue string) string { return fmt.Sprintf("/%s/messages", queue) }
func pathForMessage(queue, name string) string { return fmt.Sprintf("/%s/messages/%s", queue, name) }
type putMessageRequest struct {
XMLName xml.Name `xml:"QueueMessage"`
MessageText string `xml:"MessageText"`
}
// PutMessageParameters is the set of options can be specified for Put Messsage
// operation. A zero struct does not use any preferences for the request.
type PutMessageParameters struct {
VisibilityTimeout int
MessageTTL int
}
func (p PutMessageParameters) getParameters() url.Values {
out := url.Values{}
if p.VisibilityTimeout != 0 {
out.Set("visibilitytimeout", strconv.Itoa(p.VisibilityTimeout))
}
if p.MessageTTL != 0 {
out.Set("messagettl", strconv.Itoa(p.MessageTTL))
}
return out
}
// GetMessagesParameters is the set of options can be specified for Get
// Messsages operation. A zero struct does not use any preferences for the
// request.
type GetMessagesParameters struct {
NumOfMessages int
VisibilityTimeout int
}
func (p GetMessagesParameters) getParameters() url.Values {
out := url.Values{}
if p.NumOfMessages != 0 {
out.Set("numofmessages", strconv.Itoa(p.NumOfMessages))
}
if p.VisibilityTimeout != 0 {
out.Set("visibilitytimeout", strconv.Itoa(p.VisibilityTimeout))
}
return out
}
// PeekMessagesParameters is the set of options can be specified for Peek
// Messsage operation. A zero struct does not use any preferences for the
// request.
type PeekMessagesParameters struct {
NumOfMessages int
}
func (p PeekMessagesParameters) getParameters() url.Values {
out := url.Values{"peekonly": {"true"}} // Required for peek operation
if p.NumOfMessages != 0 {
out.Set("numofmessages", strconv.Itoa(p.NumOfMessages))
}
return out
}
// GetMessagesResponse represents a response returned from Get Messages
// operation.
type GetMessagesResponse struct {
XMLName xml.Name `xml:"QueueMessagesList"`
QueueMessagesList []GetMessageResponse `xml:"QueueMessage"`
}
// GetMessageResponse represents a QueueMessage object returned from Get
// Messages operation response.
type GetMessageResponse struct {
MessageID string `xml:"MessageId"`
InsertionTime string `xml:"InsertionTime"`
ExpirationTime string `xml:"ExpirationTime"`
PopReceipt string `xml:"PopReceipt"`
TimeNextVisible string `xml:"TimeNextVisible"`
DequeueCount int `xml:"DequeueCount"`
MessageText string `xml:"MessageText"`
}
// PeekMessagesResponse represents a response returned from Get Messages
// operation.
type PeekMessagesResponse struct {
XMLName xml.Name `xml:"QueueMessagesList"`
QueueMessagesList []PeekMessageResponse `xml:"QueueMessage"`
}
// PeekMessageResponse represents a QueueMessage object returned from Peek
// Messages operation response.
type PeekMessageResponse struct {
MessageID string `xml:"MessageId"`
InsertionTime string `xml:"InsertionTime"`
ExpirationTime string `xml:"ExpirationTime"`
DequeueCount int `xml:"DequeueCount"`
MessageText string `xml:"MessageText"`
}
// QueueMetadataResponse represents user defined metadata and queue
// properties on a specific queue.
//
// See https://msdn.microsoft.com/en-us/library/azure/dd179384.aspx
type QueueMetadataResponse struct {
ApproximateMessageCount int
UserDefinedMetadata map[string]string
}
// SetMetadata operation sets user-defined metadata on the specified queue.
// Metadata is associated with the queue as name-value pairs.
//
// See https://msdn.microsoft.com/en-us/library/azure/dd179348.aspx
func (c QueueServiceClient) SetMetadata(name string, metadata map[string]string) error {
uri := c.client.getEndpoint(queueServiceName, pathForQueue(name), url.Values{"comp": []string{"metadata"}})
headers := c.client.getStandardHeaders()
for k, v := range metadata {
headers[userDefinedMetadataHeaderPrefix+k] = v
}
resp, err := c.client.exec("PUT", uri, headers, nil)
if err != nil {
return err
}
defer resp.body.Close()
return checkRespCode(resp.statusCode, []int{http.StatusNoContent})
}
// GetMetadata operation retrieves user-defined metadata and queue
// properties on the specified queue. Metadata is associated with
// the queue as name-values pairs.
//
// See https://msdn.microsoft.com/en-us/library/azure/dd179384.aspx
//
// Because the way Golang's http client (and http.Header in particular)
// canonicalize header names, the returned metadata names would always
// be all lower case.
func (c QueueServiceClient) GetMetadata(name string) (QueueMetadataResponse, error) {
qm := QueueMetadataResponse{}
qm.UserDefinedMetadata = make(map[string]string)
uri := c.client.getEndpoint(queueServiceName, pathForQueue(name), url.Values{"comp": []string{"metadata"}})
headers := c.client.getStandardHeaders()
resp, err := c.client.exec("GET", uri, headers, nil)
if err != nil {
return qm, err
}
defer resp.body.Close()
for k, v := range resp.headers {
if len(v) != 1 {
return qm, fmt.Errorf("Unexpected number of values (%d) in response header '%s'", len(v), k)
}
value := v[0]
if k == approximateMessagesCountHeader {
qm.ApproximateMessageCount, err = strconv.Atoi(value)
if err != nil {
return qm, fmt.Errorf("Unexpected value in response header '%s': '%s' ", k, value)
}
} else if strings.HasPrefix(k, userDefinedMetadataHeaderPrefix) {
name := strings.TrimPrefix(k, userDefinedMetadataHeaderPrefix)
qm.UserDefinedMetadata[strings.ToLower(name)] = value
}
}
return qm, checkRespCode(resp.statusCode, []int{http.StatusOK})
}
// CreateQueue operation creates a queue under the given account.
//
// See https://msdn.microsoft.com/en-us/library/azure/dd179342.aspx
func (c QueueServiceClient) CreateQueue(name string) error {
uri := c.client.getEndpoint(queueServiceName, pathForQueue(name), url.Values{})
headers := c.client.getStandardHeaders()
resp, err := c.client.exec("PUT", uri, headers, nil)
if err != nil {
return err
}
defer resp.body.Close()
return checkRespCode(resp.statusCode, []int{http.StatusCreated})
}
// DeleteQueue operation permanently deletes the specified queue.
//
// See https://msdn.microsoft.com/en-us/library/azure/dd179436.aspx
func (c QueueServiceClient) DeleteQueue(name string) error {
uri := c.client.getEndpoint(queueServiceName, pathForQueue(name), url.Values{})
resp, err := c.client.exec("DELETE", uri, c.client.getStandardHeaders(), nil)
if err != nil {
return err
}
defer resp.body.Close()
return checkRespCode(resp.statusCode, []int{http.StatusNoContent})
}
// QueueExists returns true if a queue with given name exists.
func (c QueueServiceClient) QueueExists(name string) (bool, error) {
uri := c.client.getEndpoint(queueServiceName, pathForQueue(name), url.Values{"comp": {"metadata"}})
resp, err := c.client.exec("GET", uri, c.client.getStandardHeaders(), nil)
if resp != nil && (resp.statusCode == http.StatusOK || resp.statusCode == http.StatusNotFound) {
return resp.statusCode == http.StatusOK, nil
}
return false, err
}
// PutMessage operation adds a new message to the back of the message queue.
//
// See https://msdn.microsoft.com/en-us/library/azure/dd179346.aspx
func (c QueueServiceClient) PutMessage(queue string, message string, params PutMessageParameters) error {
uri := c.client.getEndpoint(queueServiceName, pathForQueueMessages(queue), params.getParameters())
req := putMessageRequest{MessageText: message}
body, nn, err := xmlMarshal(req)
if err != nil {
return err
}
headers := c.client.getStandardHeaders()
headers["Content-Length"] = strconv.Itoa(nn)
resp, err := c.client.exec("POST", uri, headers, body)
if err != nil {
return err
}
defer resp.body.Close()
return checkRespCode(resp.statusCode, []int{http.StatusCreated})
}
// ClearMessages operation deletes all messages from the specified queue.
//
// See https://msdn.microsoft.com/en-us/library/azure/dd179454.aspx
func (c QueueServiceClient) ClearMessages(queue string) error {
uri := c.client.getEndpoint(queueServiceName, pathForQueueMessages(queue), url.Values{})
resp, err := c.client.exec("DELETE", uri, c.client.getStandardHeaders(), nil)
if err != nil {
return err
}
defer resp.body.Close()
return checkRespCode(resp.statusCode, []int{http.StatusNoContent})
}
// GetMessages operation retrieves one or more messages from the front of the
// queue.
//
// See https://msdn.microsoft.com/en-us/library/azure/dd179474.aspx
func (c QueueServiceClient) GetMessages(queue string, params GetMessagesParameters) (GetMessagesResponse, error) {
var r GetMessagesResponse
uri := c.client.getEndpoint(queueServiceName, pathForQueueMessages(queue), params.getParameters())
resp, err := c.client.exec("GET", uri, c.client.getStandardHeaders(), nil)
if err != nil {
return r, err
}
defer resp.body.Close()
err = xmlUnmarshal(resp.body, &r)
return r, err
}
// PeekMessages retrieves one or more messages from the front of the queue, but
// does not alter the visibility of the message.
//
// See https://msdn.microsoft.com/en-us/library/azure/dd179472.aspx
func (c QueueServiceClient) PeekMessages(queue string, params PeekMessagesParameters) (PeekMessagesResponse, error) {
var r PeekMessagesResponse
uri := c.client.getEndpoint(queueServiceName, pathForQueueMessages(queue), params.getParameters())
resp, err := c.client.exec("GET", uri, c.client.getStandardHeaders(), nil)
if err != nil {
return r, err
}
defer resp.body.Close()
err = xmlUnmarshal(resp.body, &r)
return r, err
}
// DeleteMessage operation deletes the specified message.
//
// See https://msdn.microsoft.com/en-us/library/azure/dd179347.aspx
func (c QueueServiceClient) DeleteMessage(queue, messageID, popReceipt string) error {
uri := c.client.getEndpoint(queueServiceName, pathForMessage(queue, messageID), url.Values{
"popreceipt": {popReceipt}})
resp, err := c.client.exec("DELETE", uri, c.client.getStandardHeaders(), nil)
if err != nil {
return err
}
defer resp.body.Close()
return checkRespCode(resp.statusCode, []int{http.StatusNoContent})
}
