Set caching headers on asm API requests

app.js

@@ -24,24 +24,22 @@
 // ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
 // POSSIBILITY OF SUCH DAMAGE.
 
-// load external and internal libraries (will load more internal binaries later)
+// Initialise options and properties. Don't load any handlers here; they
+// may need an initialised properties library.
 var nopt = require('nopt'),
     os = require('os'),
     props = require('./lib/properties'),
-    CompileHandler = require('./lib/compile-handler').CompileHandler,
-    express = require('express'),
     child_process = require('child_process'),
     path = require('path'),
     fs = require('fs-extra'),
     http = require('http'),
     https = require('https'),
     url = require('url'),
-    utils = require('./lib/utils'),
     Promise = require('promise'),
-    aws = require('./lib/aws'),
     _ = require('underscore-node'),
-    logger = require('./lib/logger').logger,
-    asm_doc_api = require('./lib/asm-docs-api');
+    utils = require('./lib/utils'),
+    express = require('express'),
+    logger = require('./lib/logger').logger;
 
 // Parse arguments from command line 'node ./app.js args...'
 var opts = nopt({
@@ -89,6 +87,11 @@ if (opts.propDebug) props.setDebug(true);
 // *All* files in config dir are parsed 
 props.initialize(rootDir + '/config', propHierarchy);
 
+// Now load up our libraries.
+var CompileHandler = require('./lib/compile-handler').CompileHandler,
+    aws = require('./lib/aws'),
+    asm_doc_api = require('./lib/asm-docs-api');
+
 // Instantiate a function to access records concerning "compiler-explorer" 
 // in hidden object props.properties
 var gccProps = props.propsFor("compiler-explorer");

etc/config/asm-docs.amazon.properties

@@ -0,0 +1 @@
+staticMaxAgeSecs=3600

etc/config/asm-docs.defaults.properties

@@ -0,0 +1 @@
+staticMaxAgeSecs=10

lib/asm-docs-api.js

@@ -24,8 +24,12 @@
 // POSSIBILITY OF SUCH DAMAGE.
 
 var asm_doc = require('./asm-docs');
+var props = require('./properties');
 
-function docHandler(req, res) {
+var asmProps = props.propsFor("asm-docs");
+var staticMaxAgeSecs = asmProps('staticMaxAgeSecs', 10);
+
+function docHandler(req, res, next) {
     var info = asm_doc.getAsmOpcode(req.params.opcode);
     if (!info) {
         // If the opcode ends with an AT&T suffix, try removing that and giving it another go.
@@ -36,6 +40,12 @@ function docHandler(req, res) {
             info = asm_doc.getAsmOpcode(suffixRemoved[1]);
         }
     }
+    if (staticMaxAgeSecs) {
+        res.setHeader('Cache-Control', 'public, max-age=' + staticMaxAgeSecs);
+    }
+    if (!info) {
+        return res.status(404).send("Unknown opcode");
+    }
     if (req.accepts(['text', 'json']) == 'json') {
         res.set('Content-Type', 'application/json');
         res.end(JSON.stringify(info));