diff --git a/scripts/build_web_assets.py b/scripts/build_web_assets.py
index 9cad070..58a9b94 100755
--- a/scripts/build_web_assets.py
+++ b/scripts/build_web_assets.py
@@ -5,17 +5,19 @@
 import gzip
 import hashlib
 from subprocess import Popen, PIPE
+import re
 
 THIS_DIR = os.path.dirname(os.path.realpath(__file__))
 
-ENABLE_CACHING = False
+ENABLE_CACHING = True
 
-# TODO this needs to be better
+# TODO(ed) this needs to be better
 CONTENT_TYPES = {
     '.css': "text/css;charset=UTF-8",
     '.html': "text/html;charset=UTF-8",
     '.js': "text/html;charset=UTF-8",
-    '.png': "image/png;charset=UTF-8"
+    '.png': "image/png;charset=UTF-8",
+    '.woff': "application/x-font-woff",
 }
 
 CPP_BEGIN_BUFFER = """
@@ -23,25 +25,46 @@
 
 """
 
-ROUTE_DECLARATION = """void crow::webassets::request_routes(crow::App<crow::TokenAuthorizationMiddleware>& app){
+ROUTE_DECLARATION = """
+
+void crow::webassets::request_routes(BmcAppType& app){
 """
 
+CPP_MIDDLE_CACHING_HANDLER = """
+        res.add_header("Cache-Control", "public, max-age=31556926");
+        res.add_header("ETag", "{sha1}");
+        if (req.headers.count("If-None-Match") == 1) {{
+            if (req.get_header_value("If-None-Match") == "{sha1}"){{
+                res.code = 304;
+                res.end();
+                return;
+            }}
+        }}
+"""
+
+
 CPP_MIDDLE_BUFFER = """
     CROW_ROUTE(app, "{relative_path_sha1}")([](const crow::request& req, crow::response& res) {{
+        {CPP_MIDDLE_CACHING_HANDLER}
         res.code = 200;
         // TODO, if you have a browser from the dark ages that doesn't support gzip,
         // unzip it before sending based on Accept-Encoding header
-        res.add_header("Content-Encoding", "gzip");
-        res.add_header("Cache-Control", "{cache_control_value}");
+        res.add_header("Content-Encoding", "{content_encoding}");
         res.add_header("Content-Type", "{content_type}");
 
         res.write({relative_path_escaped});
-        res.end();
         
+        res.end();
     }});
 """
 
 
+def twos_comp(val, bits):
+    """compute the 2's compliment of int value val"""
+    if (val & (1 << (bits - 1))) != 0: # if sign bit is set e.g., 8bit: 128-255
+        val = val - (1 << bits)        # compute negative value
+    return val                         # return positive value as is
+
 CPP_END_BUFFER = """
 }
 """
@@ -52,62 +75,57 @@
 def get_relative_path(full_filepath):
     pathsplit = full_filepath.split(os.path.sep)
     relative_path = os.path.sep.join(pathsplit[pathsplit.index("static") + 1:])
-
-    relative_path_escaped = relative_path.replace("/", "_").replace(".", "_").replace("-", "_")
+    relative_path_escaped = relative_path
+    for character in ['/', '.', '-']:
+        relative_path_escaped = relative_path_escaped.replace(character, "_")
 
     relative_path = "/static/" + relative_path
 
-    # handle the default routes
-    if relative_path == "/static/index.html":
-        relative_path = "/"
-
     return relative_path, relative_path_escaped
 
 def get_sha1_path_from_relative(relative_path, sha1):
     if sha1 != "":
         path, extension = os.path.splitext(relative_path)
-        return path + "_" + sha1 + extension
+        return path + "-" + sha1[:10] + extension
     else:
         return relative_path
 
-
 def filter_html(sha1_list, file_content):
     string_content = file_content.decode()
     for key, value in sha1_list.items():
-        if key != "/":
-            # todo, this is very naive, do it better (parse the html)
-            start = "src=\"" + key.lstrip("/")
-            replace = "src=\"" + get_sha1_path_from_relative(key, value)
-            #print("REplacing {} with {}".format(start, replace))
-            string_content = string_content.replace(start, replace)
-
-            start = "href=\"" + key.lstrip("/")
-            replace = "href=\"" + get_sha1_path_from_relative(key, value)
-            #print("REplacing {} with {}".format(start, replace))
-            string_content = string_content.replace(start, replace)
+        key = key.lstrip("/")
+        replace_name = get_sha1_path_from_relative(key, value)
+        key = re.escape(key)
+        string_content = re.sub("((src|href)=[\"'])(" + key + ")([\"'])", "\\1" + replace_name + "\\4", string_content)
     return string_content.encode()
 
+
 def main():
     """ Main Function """
 
     parser = argparse.ArgumentParser()
     parser.add_argument('-i', '--input', nargs='+', type=str)
     parser.add_argument('-o', '--output', type=str)
+    parser.add_argument('-d', '--debug', action='store_true')
     args = parser.parse_args()
 
     file_list = args.input
 
+    file_list = [os.path.realpath(f) for f in file_list]
+
     sha1_list = {}
-    if ENABLE_CACHING:
-        # Sha256 hash everthing
+    if not args.debug:
+        # TODO(ed) most html and woff cacheable
+        excluded_types = [".html", ".woff"]
+        # sha1 hash everthing
         for full_filepath in file_list:
-            if not full_filepath.endswith(".html"):
+            if os.path.splitext(full_filepath)[1] not in excluded_types:
                 with open(full_filepath, 'rb') as input_file:
                     file_content = input_file.read()
-                sha = hashlib.sha256()
+                sha = hashlib.sha1()
                 sha.update(file_content)
 
-                sha_text = "".join("{:02x}".format(x) for x in sha.digest())[:10]
+                sha_text = "".join("{:02x}".format(x) for x in sha.digest())
                 relative_path, relative_path_escaped = get_relative_path(full_filepath)
                 sha1_list[relative_path] = sha_text
 
@@ -126,13 +144,20 @@
                 print("Fixing {}".format(relative_path))
                 file_content = filter_html(sha1_list, file_content)
 
+            if not args.debug:
+                file_content = gzip.compress(file_content)
+                #file_content = file_content[:10]
+                # compute the 2s complement.  If you don't, you get narrowing warnings from gcc/clang
+            
+            array_binary_text = ', '.join(str(twos_comp(x, 8)) for x in file_content)
 
-            file_content = gzip.compress(file_content)
-            #file_content = file_content[:10]
-
-            array_binary_text = ', '.join('0x{:02x}'.format(x) for x in file_content)
-
-            cpp_output.write(CPP_END_BUFFER2.format(relative_path=relative_path, file_bytes=array_binary_text, relative_path_escaped=relative_path_escaped))
+            cpp_output.write(
+                CPP_END_BUFFER2.format(
+                    relative_path=relative_path,
+                    file_bytes=array_binary_text,
+                    relative_path_escaped=relative_path_escaped
+                )
+            )
 
         cpp_output.write(ROUTE_DECLARATION)
 
@@ -141,24 +166,37 @@
             relative_path, relative_path_escaped = get_relative_path(full_filepath)
             sha1 = sha1_list.get(relative_path, '')
 
-            relative_path_sha1 = get_sha1_path_from_relative(relative_path, sha1)
-
             content_type = CONTENT_TYPES.get(os.path.splitext(relative_path)[1], "")
             if content_type == "":
                 print("unknown content type for {}".format(relative_path))
 
-            if sha1 == "":
-                cache_control_value = "no-cache"
+            # handle the default routes
+            if relative_path == "/static/index.html":
+                relative_path = "/"
+
+            relative_path_sha1 = get_sha1_path_from_relative(relative_path, sha1)
+
+            content_encoding = 'none' if args.debug else 'gzip'
+
+            environment = {
+                'relative_path':relative_path,
+                'relative_path_escaped': relative_path_escaped,
+                'relative_path_sha1': relative_path_sha1,
+                'sha1': sha1,
+                'sha1_short': sha1[:20],
+                'content_type': content_type,
+                'ENABLE_CACHING': str(ENABLE_CACHING).lower(),
+                'content_encoding': ''
+            }
+            if ENABLE_CACHING and sha1 != "":
+                environment["CPP_MIDDLE_CACHING_HANDLER"] = CPP_MIDDLE_CACHING_HANDLER.format(
+                    **environment
+                )
             else:
-                cache_control_value = "max-age=31556926"
+                environment["CPP_MIDDLE_CACHING_HANDLER"] = ""
 
             content = CPP_MIDDLE_BUFFER.format(
-                relative_path=relative_path,
-                relative_path_escaped=relative_path_escaped,
-                relative_path_sha1=relative_path_sha1,
-                sha1=sha1,
-                content_type=content_type,
-                cache_control_value=cache_control_value
+                **environment
             )
             cpp_output.write(content)