Add parameter file_field_name

This commit add the possibility to define another upload field name
instead of the predefined myFile

Author: git001

README.adoc

@@ -27,6 +27,9 @@ In this handler are the following modules in use.
 |**dest_dir**
 |The directory in which the files will be uploaded
 
+|**file_field_name**
+|The field name for the multi-part form upload
+
 |**response_template**
 |The response template after a upload was successfully
 
@@ -50,7 +53,7 @@ In this handler are the following modules in use.
   Default is false which implies that a valid CA must be used
 
 |**capath**
-|This is the Parameter where you can define the CA for the **notify_url**.
+|This is the Parameter where you can define the CA filename for the **notify_url**.
 |===
 
 === JSON

upload.go

@@ -15,7 +15,7 @@ import (
 )
 
 const (
-	Version = "0.4"
+	Version = "0.5"
 )
 
 func init() {
@@ -27,6 +27,7 @@ func init() {
 // uploaded file  to a file on the disk.
 type Upload struct {
 	DestDir          string `json:"dest_dir,omitempty"`
+	FileFieldName    string `json:"file_field_name,omitempty"`
 	MaxFilesize      int64  `json:"max_filesize,omitempty"`
 	MaxFormBuffer    int64  `json:"max_form_buffer,omitempty"`
 	ResponseTemplate string `json:"response_template,omitempty"`
@@ -71,6 +72,13 @@ func (u *Upload) Provision(ctx caddy.Context) error {
 		return mdall_err
 	}
 
+	if u.FileFieldName == "" {
+		u.logger.Warn("Provision",
+			zap.String("msg", "no FileFieldName specified (file_field_name), using the default one 'myFile'"),
+		)
+		u.FileFieldName = "myFile"
+	}
+
 	if u.ResponseTemplate == "" {
 		u.logger.Warn("Provision",
 			zap.String("msg", "no ResponseTemplate specified (response_template), using the default one"),
@@ -133,10 +141,10 @@ func (u Upload) ServeHTTP(w http.ResponseWriter, r *http.Request, next caddyhttp
 		return caddyhttp.Error(http.StatusRequestEntityTooLarge, max_size_err)
 	}
 
-	// FormFile returns the first file for the given key `myFile`
+	// FormFile returns the first file for the given file field key
 	// it also returns the FileHeader so we can get the Filename,
 	// the Header and the size of the file
-	file, handler, ff_err := r.FormFile("myFile")
+	file, handler, ff_err := r.FormFile(u.FileFieldName)
 	if ff_err != nil {
 		u.logger.Error("FormFile Error",
 			zap.String("requuid", requuid),
@@ -216,6 +224,10 @@ func (u *Upload) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
 				if !d.Args(&u.DestDir) {
 					return d.ArgErr()
 				}
+			case "file_field_name":
+				if !d.Args(&u.FileFieldName) {
+					return d.ArgErr()
+				}
 			case "max_form_buffer":
 				var sizeStr string
 				if !d.AllArgs(&sizeStr) {