Adds readme example and fixes logical error in execute

README.md

@@ -1,5 +1,39 @@
 # Mailcap
 
-This is a stub for a Go implementation of the Python3 mailcap library. The goal is to enable the opening of files based on mimetype from programs written in golang.
+Golang port of the Python3 mailcap library.
+
+## Usage
+
+An eaxmple showing how to launch a program based on its mime/media type:
+
+```
+import(
+    tildegit.org/sloum/mailcap
+)
+
+func main() {
+  // Build the mailcap database
+  mc := mailcap.NewMailcap()
+
+  // Find an avialable command with the required key and gui avialability
+  command, err := mc.FindMatch("text/plain", "edit", false)
+  if err != nil {
+    panic(err)
+  }
+
+  // Run the command with the filepath provided
+  err := command.Execute("/var/www/index.html")
+  if err != nil {
+    panic(err)
+  }
+
+  // Now that the user has been presented the file to edit,
+  // something can be done with the updated file...
+}
+```
+
+In general usage a user will build the mailcap db, find a match, and execute the command they find with a certain filepath.
+
+A few other helper methods are available for debugging or lower level mailcap work.
 
 

mailcap.go

@@ -36,11 +36,17 @@ func (m *Mailcap) GetAllMime(mime string) (Fields, error) {
 // Retrieves an Entry for a given mimetype and key.
 // Key is required to make sure the returned Entry has
 // the capability that is desired. Common keys: "view", "edit".
+// Also takes a bool, needsTerm, that can be set to true if the
+// command must be executable in a terminal only environment.
+//
 // Returns and Entry and an error
-func (m *Mailcap) FindMatch(mime, key string) (Entry, error) {
+func (m *Mailcap) FindMatch(mime, key string, needsTerm bool) (Entry, error) {
 	entries := m.lookup(mime, key)
 	for _, v := range entries {
 		exitCode := 0;
+		if _, ok := v["needsterminal"]; needsTerm && !ok {
+			continue
+		}
 		if t, ok := v["test"]; ok {
 			cmdArgs := strings.Split(t, " ")
 			if len(cmdArgs) < 2 {
@@ -57,6 +63,7 @@ func (m *Mailcap) FindMatch(mime, key string) (Entry, error) {
 		if exitCode != 0 {
 			continue
 		}
+		v["action"] = key
 		return v, nil
 	}
 
@@ -70,13 +77,17 @@ func (m *Mailcap) FindMatch(mime, key string) (Entry, error) {
 // to declare the target of the program being
 // called via the key param. Returns an error
 // or nil.
-func (e Entry) Execute(key, path string) error {
-	entryVal, ok := e[key]
+func (e Entry) Execute(path string) error {
+	key, ok := e["action"]
 	if !ok {
-		return fmt.Errorf("The key %q does not exist", key)
+		return fmt.Errorf("No action has been set for this entry, was the entry returned by FindMatch?")
 	} 
+	command, ok := e[key]
+	if !ok {
+		return fmt.Errorf("Entry does not have the key %q", key)
+	}
 
-	matchFields := strings.Fields(entryVal)
+	matchFields := strings.Fields(command)
 	for index, field := range matchFields {
 		if field == "%s" || field == "'%s'" {
 			matchFields[index] = path
@@ -96,6 +107,14 @@ func (e Entry) Execute(key, path string) error {
 	return nil
 }
 
+func (e Entry) SetAction(action string) error {
+	if _, ok := e[action]; !ok {
+		return fmt.Errorf("This entry does not have the action %q available", action)
+	}
+	e["action"] = action
+	return nil
+}
+
 // Look up all of the Entry types available for 
 // a given mime and key. Returns an Entry slice (Fields)
 func (m *Mailcap) lookup(mime, key string) Fields {