Get source mimetype from sourceuri

main.go

@@ -45,7 +45,11 @@ func MessageHandler(w http.ResponseWriter, r *http.Request) {
 	defer r.Body.Close()
 
 	// Read the Alpaca message payload
-	message, err := api.DecodeAlpacaMessage(r)
+	auth := ""
+	if config.ForwardAuth {
+		auth = r.Header.Get("Authorization")
+	}
+	message, err := api.DecodeAlpacaMessage(r, auth)
 	if err != nil {
 		slog.Error("Error decoding Pub/Sub message", "err", err)
 		http.Error(w, "Internal error", http.StatusInternalServerError)
@@ -60,7 +64,7 @@ func MessageHandler(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 	if config.ForwardAuth {
-		req.Header.Set("Authorization", r.Header.Get("Authorization"))
+		req.Header.Set("Authorization", auth)
 	}
 	sourceResp, err := http.DefaultClient.Do(req)
 	if err != nil {
@@ -76,7 +80,7 @@ func MessageHandler(w http.ResponseWriter, r *http.Request) {
 	}
 
 	// build a command to run that we will pipe the stdin stream into
-	cmd, err := scyllaridae.BuildExecCommand(message.Attachment.Content.MimeType, message.Attachment.Content.Args, config)
+	cmd, err := scyllaridae.BuildExecCommand(message.Attachment.Content.SourceMimeType, message.Attachment.Content.Args, config)
 	if err != nil {
 		slog.Error("Error building command", "err", err)
 		http.Error(w, "Internal error", http.StatusInternalServerError)

main_test.go

@@ -147,7 +147,7 @@ cmdByMimeType:
 			destinationServer := createMockDestinationServer(tt.returnedBody)
 			defer destinationServer.Close()
 
-			sourceServer := createMockSourceServer(t, tt.authHeader, destinationServer.URL)
+			sourceServer := createMockSourceServer(t, tt.mimetype, tt.authHeader, destinationServer.URL)
 			defer sourceServer.Close()
 
 			os.Setenv("SCYLLARIDAE_YML", tt.yml)
@@ -168,7 +168,8 @@ cmdByMimeType:
 				t.Fatal(err)
 			}
 			req.Header.Set("X-Islandora-Args", destinationServer.URL)
-			req.Header.Set("Accept", tt.mimetype)
+			// set the mimetype to send to the destination server in the Accept header
+			req.Header.Set("Accept", "application/xml")
 			req.Header.Set("Authorization", tt.requestAuth)
 			req.Header.Set("Apix-Ldp-Resource", sourceServer.URL)
 
@@ -192,13 +193,14 @@ func createMockDestinationServer(content string) *httptest.Server {
 	}))
 }
 
-func createMockSourceServer(t *testing.T, auth, content string) *httptest.Server {
+func createMockSourceServer(t *testing.T, mimetype, auth, content string) *httptest.Server {
 	return httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		if config.ForwardAuth && r.Header.Get("Authorization") != auth {
 			w.WriteHeader(http.StatusUnauthorized)
 			return
 		}
 
+		w.Header().Set("Content-Type", mimetype)
 		if _, err := w.Write([]byte(content)); err != nil {
 			t.Fatal("Failed to write response in mock server")
 		}

pkg/api/events.go

@@ -1,6 +1,8 @@
 package api
 
 import (
+	"fmt"
+	"log/slog"
 	"net/http"
 )
 
@@ -55,24 +57,55 @@ type Attachment struct {
 //
 // swagger:model Content
 type Content struct {
-	MimeType       string `json:"mimetype" description:"MIME type of the content"`
-	Args           string `json:"args" description:"Arguments used or applicable to the content"`
-	SourceURI      string `json:"sourceUri" description:"Source URI from which the content is fetched"`
-	DestinationURI string `json:"destinationUri" description:"Destination URI to where the content is delivered"`
-	FileUploadURI  string `json:"fileUploadUri" description:"File upload URI for uploading the content"`
+	SourceMimeType      string `json:"source_mimetype,omitempty" description:"MIME type of the source URI"`
+	DestinationMimeType string `json:"mimetype" description:"MIME type of the derivative being created"`
+	Args                string `json:"args" description:"Arguments used or applicable to the content"`
+	SourceURI           string `json:"sourceUri" description:"Source URI from which the content is fetched"`
+	DestinationURI      string `json:"destinationUri" description:"Destination URI to where the content is delivered"`
+	FileUploadURI       string `json:"fileUploadUri" description:"File upload URI for uploading the content"`
 }
 
-func DecodeAlpacaMessage(r *http.Request) (Payload, error) {
+func DecodeAlpacaMessage(r *http.Request, auth string) (Payload, error) {
 	p := Payload{}
 
 	// set the payload based on the headers alpaca sends to this service
 	p.Attachment.Content.Args = r.Header.Get("X-Islandora-Args")
 	p.Attachment.Content.SourceURI = r.Header.Get("Apix-Ldp-Resource")
-	mimetype := r.Header.Get("Accept")
-	if mimetype == "" {
-		mimetype = "text/plain"
+
+	p.Attachment.Content.DestinationMimeType = r.Header.Get("Accept")
+	if p.Attachment.Content.DestinationMimeType == "" {
+		p.Attachment.Content.DestinationMimeType = "text/plain"
+	}
+
+	err := p.getSourceUri(auth)
+	if err != nil {
+		return p, err
 	}
-	p.Attachment.Content.MimeType = mimetype
 
 	return p, nil
 }
+
+func (p *Payload) getSourceUri(auth string) error {
+	client := &http.Client{}
+
+	req, err := http.NewRequest("HEAD", p.Attachment.Content.SourceURI, nil)
+	if err != nil {
+		slog.Error("Unable to create source URI request", "uri", p.Attachment.Content.SourceURI, "err", err)
+		return fmt.Errorf("error creating request for %s", p.Attachment.Content.SourceURI)
+	}
+
+	if auth != "" {
+		req.Header.Set("Authorization", auth)
+	}
+
+	resp, err := client.Do(req)
+	if err != nil {
+		slog.Error("Unable to get source URI", "uri", p.Attachment.Content.SourceURI, "err", err)
+		return fmt.Errorf("error issuing HEAD request on %s", p.Attachment.Content.SourceURI)
+	}
+	defer resp.Body.Close()
+
+	p.Attachment.Content.SourceMimeType = resp.Header.Get("Content-Type")
+	slog.Info("Got mimetype", "mime", p.Attachment.Content.SourceMimeType)
+	return nil
+}