prevent URL length limit errors

Closes #829

lib/routing.js

@@ -3,6 +3,7 @@ import url from 'url'
 
 import { escapeHtml } from './util'
 
+const URL_LIMIT = 4e3
 const mapper = new Morph({
   types: {
     bool: v => {
@@ -29,7 +30,12 @@ const mapper = new Morph({
     encode: v => {
       if (v == null) return undefined
       try {
-        return encodeURIComponent(v)
+        const encoded = encodeURIComponent(v)
+        if (encoded.length > URL_LIMIT) {
+          // soft prevent URL length limit errors https://github.com/dawnlabs/carbon/issues/829
+          return encodeURIComponent(v.slice(0, URL_LIMIT / 2))
+        }
+        return encoded
       } catch (e) {
         return v
       }