fixes not concerning graphics

- default is no graphics
- use send_file instead of response (proper mimetype)
- fix issues with parameter blocks

seaweb.py

@@ -37,6 +37,7 @@ def guess_mimetype(filename):
         mimetype = 'text/css'
     elif filename.endswith('.ico'):
         mimetype = 'image/x-icon'
+        print('mimetype', mimetype)
     else:
         mimetype = 'text/html'
     return mimetype
@@ -141,12 +142,7 @@ def reply():
 @app.route('/test/<file>')
 def subdir_test_file(file):
     gevent.sleep(2)
-    try:
-        with open("client/test/"+file, 'r') as content_file:
-            content = content_file.read()
-    except IOError:
-        flask.abort(404)
-    resp = flask.Response(content, mimetype=guess_mimetype(file))
+    resp = flask.send_file("client/test/"+file, mimetype=guess_mimetype(file))
     return resp
 
 @app.route('/jsFiles/<file>')
@@ -154,12 +150,7 @@ def subdir_test_file(file):
 @app.route('/externalFiles/<file>')
 def subdir_file(file):
     subdir = flask.request.path.split('/')[1]
-    try:
-        with open("client/" + subdir+"/"+file, 'r') as content_file:
-            content = content_file.read()
-    except IOError:
-        flask.abort(404)
-    resp = flask.Response(content, mimetype=guess_mimetype(file))
+    resp = flask.send_file("client/" + subdir+"/"+file, mimetype=guess_mimetype(file))
     #resp.headers['Content-Security-Policy'] = "sandbox; script-src 'unsafe-inline';"
     return resp
 
@@ -174,12 +165,7 @@ def default():
 @app.route('/<file>')
 def general_file(file):
     subdir = "client/"
-    try:
-        with open(subdir+file, 'r') as content_file:
-            content = content_file.read()
-    except IOError:
-        flask.abort(404)
-    resp = flask.Response(content, mimetype=guess_mimetype(file))
+    resp = flask.send_file(subdir+file, mimetype=guess_mimetype(file))
     #resp.headers['Content-Security-Policy'] = "sandbox; script-src 'unsafe-inline';"
     return resp
 
@@ -332,7 +318,7 @@ class SeaInstrument(Instrument):
         
     def poll_groups(self, paths):
         'polls values and components of requested groups'
-        for path in paths:
+        for path in list(paths):
             gobj = self.groups[path]
             now = time.time()
             if now < gobj.lastpoll + 0.5:
@@ -627,7 +613,9 @@ class SeaClient(SeaGraph):
         
     def w_getblock(self, path):
         gobj = instrument.findgroup(path.split(',')[-1])
-        self.group_version[path] = gobj.version
+        # self.group_version[path] = gobj.version
+        # simplify: allow only one group per client
+        self.group_version = {path: gobj.version}
         logging.info('getblock %s %d', path, gobj.version)
         return dict(type='draw', title=gobj.grouptitle, path=path, components=gobj.components)