More documentation and a tiny refactor

README.md

@@ -10,7 +10,7 @@ Define the service's behavior in `scyllaridae.yml`.
 
 You can specify which mimetypes the service can act on in `allowedMimeTypes`
 
-And specify different commands for different mimetypes in `cmdByMimeType`, or set the default command to run for all mimetypes with the `default` key.
+And specify different commands for different mimetypes in `cmdByMimeType`, or set the default command to run for all mimetypes with the `default` key. Here's another more [complex example YML](./scyllaridae.complex.yml).
 
 ```yaml
 allowedMimeTypes:
@@ -21,8 +21,10 @@ cmdByMimeType:
     args:
       - "-X"
       - "POST"
+      # read the source media file in from stdin
       - "-F"
       - "datafile=@-"
+      # send the media file to FITS which will return the XML to stdout
       - "http://fits:8080/fits/examine"
 ```
 

internal/config/server.go

@@ -109,13 +109,11 @@ func ReadConfig(yp string) (*ServerConfig, error) {
 }
 
 func BuildExecCommand(mimetype, addtlArgs string, c *ServerConfig) (*exec.Cmd, error) {
-	var cmdConfig Command
-	var exists bool
 	if !IsAllowedMimeType(mimetype, c.AllowedMimeTypes) {
 		return nil, fmt.Errorf("undefined mimetype: %s", mimetype)
 	}
 
-	cmdConfig, exists = c.CmdByMimeType[mimetype]
+	cmdConfig, exists := c.CmdByMimeType[mimetype]
 	if !exists {
 		cmdConfig = c.CmdByMimeType["default"]
 	}

scyllaridae.complex.yml

@@ -7,11 +7,15 @@ cmdByMimeType:
     cmd: convert
     args:
       - "pdf:-[0]"
+      # %s is a special string used by scyllaridae
+      # populated by the X-Islandora-Args HTTP header
       - "%s"
       - "pdf:-"
   default:
     cmd: convert
     args:
       - "-"
+      # %s is a special string used by scyllaridae
+      # populated by the X-Islandora-Args HTTP header
       - "%s"
       - "image:-"