Add downloads endpoint API call

client.go

@@ -251,6 +251,44 @@ func (c *Client) DoUpdate(ctx context.Context, creds Credentials) ([]byte, []byt
 	return result.Config, dhPrivkeyPEM, newCreds, nil
 }
 
+// DetermineLatestVersion returns the latest version information.
+func (c *Client) DetermineLatestVersion(ctx context.Context, logger logrus.FieldLogger) (*message.DownloadsResponseLatest, error) {
+	logger.WithFields(logrus.Fields{"server": c.dnServer}).Debug("Finding latest DNClient version")
+
+	req, err := http.NewRequestWithContext(ctx, "GET", c.dnServer+message.EnrollEndpoint, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	resp, err := c.http.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	// Log the request ID returned from the server
+	reqID := resp.Header.Get("X-Request-ID")
+	logger.WithFields(logrus.Fields{"reqID": reqID}).Debug("Request for latest DNClient version complete")
+
+	// Decode the response
+	r := message.DownloadsResponse{}
+	b, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, &APIError{e: fmt.Errorf("error reading response body: %s", err), ReqID: reqID}
+	}
+
+	if err := json.Unmarshal(b, &r); err != nil {
+		return nil, &APIError{e: fmt.Errorf("error decoding JSON response: %s\nbody: %s", err, b), ReqID: reqID}
+	}
+
+	// Check for any errors returned by the API
+	if err := r.Errors.ToError(); err != nil {
+		return nil, &APIError{e: fmt.Errorf("unexpected error during downloads fetch: %v", err), ReqID: reqID}
+	}
+
+	return &r.Data.VersionInfo.Latest, nil
+}
+
 // postDNClient wraps and signs the given dnclientRequestWrapper message, and makes the API call.
 // On success, it returns the response message body. On error, the error is returned.
 func (c *Client) postDNClient(ctx context.Context, reqType string, value []byte, hostID string, counter uint, privkey ed25519.PrivateKey) ([]byte, error) {

message/api.go

@@ -0,0 +1,102 @@
+package message
+
+import (
+	"errors"
+	"strings"
+	"time"
+)
+
+// EnrollEndpoint is the REST enrollment endpoint.
+const EnrollEndpoint = "/v2/enroll"
+
+// APIError represents a single error returned in an API error response.
+type APIError struct {
+	Code    string `json:"code"`
+	Message string `json:"message"`
+	Path    string `json:"path"` // may or may not be present
+}
+
+type APIErrors []APIError
+
+func (errs APIErrors) ToError() error {
+	if len(errs) == 0 {
+		return nil
+	}
+
+	s := make([]string, len(errs))
+	for i := range errs {
+		s[i] = errs[i].Message
+	}
+
+	return errors.New(strings.Join(s, ", "))
+}
+
+// EnrollRequest is issued to the EnrollEndpoint.
+type EnrollRequest struct {
+	Code      string    `json:"code"`
+	DHPubkey  []byte    `json:"dhPubkey"`
+	EdPubkey  []byte    `json:"edPubkey"`
+	Timestamp time.Time `json:"timestamp"`
+}
+
+// EnrollResponse represents a response from the enrollment endpoint.
+type EnrollResponse struct {
+	// Only one of Data or Errors should be set in a response
+	Data EnrollResponseData `json:"data"`
+
+	Errors APIErrors `json:"errors"`
+}
+
+// EnrollResponseData is included in the EnrollResponse.
+type EnrollResponseData struct {
+	Config       []byte                `json:"config"`
+	HostID       string                `json:"hostID"`
+	Counter      uint                  `json:"counter"`
+	TrustedKeys  []byte                `json:"trustedKeys"`
+	Organization EnrollResponseDataOrg `json:"organization"`
+}
+
+// EnrollResponseDataOrg is included in EnrollResponseData.
+type EnrollResponseDataOrg struct {
+	ID   string `json:"id"`
+	Name string `json:"name"`
+}
+
+type DownloadsResponse struct {
+	// Only one of Data or Errors should be set in a response
+	Data DownloadsResponseData `json:"data"`
+
+	Errors APIErrors `json:"errors"`
+}
+
+type DownloadsResponseData struct {
+	// DNClient maps versions to a map of platforms' download links.
+	DNClient map[string]map[string]string `json:"dnclient"`
+	// Mobile maps platforms to their download links (i.e. App Store / Play Store.)
+	Mobile DownloadsResponseMobile `json:"mobile"`
+
+	// VersionInfo contains information about past versions.
+	VersionInfo DownloadsResponseVersionInfo `json:"versionInfo"`
+}
+
+type DownloadsResponseVersionInfo struct {
+	// DNClient maps versions to their version info.
+	DNClient map[string]DNClientVersionInfo `json:"dnclient"`
+	// Latest returns the latest versions for each platform.
+	Latest DownloadsResponseLatest `json:"latest"`
+}
+
+type DownloadsResponseMobile struct {
+	Android string `json:"android"`
+	IOS     string `json:"ios"`
+}
+
+type DownloadsResponseLatest struct {
+	DNClient string `json:"dnclient"`
+	Mobile   string `json:"mobile"`
+}
+
+type DNClientVersionInfo struct {
+	Latest      bool   `json:"latest"`
+	ReleaseDate string `json:"releaseDate"`
+}

message/message.go → message/dnclient.go

@@ -1,10 +1,6 @@
 package message
 
-import (
-	"errors"
-	"strings"
-	"time"
-)
+import "time"
 
 // DNClient API message types
 const (
@@ -72,59 +68,3 @@ type DoUpdateResponse struct {
 	Nonce       []byte `json:"nonce"`
 	TrustedKeys []byte `json:"trustedKeys"`
 }
-
-// EnrollEndpoint is the REST enrollment endpoint.
-const EnrollEndpoint = "/v2/enroll"
-
-// EnrollRequest is issued to the EnrollEndpoint.
-type EnrollRequest struct {
-	Code      string    `json:"code"`
-	DHPubkey  []byte    `json:"dhPubkey"`
-	EdPubkey  []byte    `json:"edPubkey"`
-	Timestamp time.Time `json:"timestamp"`
-}
-
-// EnrollResponse represents a response from the enrollment endpoint.
-type EnrollResponse struct {
-	// Only one of Data or Errors should be set in a response
-	Data EnrollResponseData `json:"data"`
-
-	Errors APIErrors `json:"errors"`
-}
-
-// EnrollResponseData is included in the EnrollResponse.
-type EnrollResponseData struct {
-	Config       []byte                `json:"config"`
-	HostID       string                `json:"hostID"`
-	Counter      uint                  `json:"counter"`
-	TrustedKeys  []byte                `json:"trustedKeys"`
-	Organization EnrollResponseDataOrg `json:"organization"`
-}
-
-// EnrollResponseDataOrg is included in EnrollResponseData.
-type EnrollResponseDataOrg struct {
-	ID   string `json:"id"`
-	Name string `json:"name"`
-}
-
-// APIError represents a single error returned in an API error response.
-type APIError struct {
-	Code    string `json:"code"`
-	Message string `json:"message"`
-	Path    string `json:"path"` // may or may not be present
-}
-
-type APIErrors []APIError
-
-func (errs APIErrors) ToError() error {
-	if len(errs) == 0 {
-		return nil
-	}
-
-	s := make([]string, len(errs))
-	for i := range errs {
-		s[i] = errs[i].Message
-	}
-
-	return errors.New(strings.Join(s, ", "))
-}