Merge pull request #83 from dirtbags/81-support-downloading-open-content

Support downloading open content

CHANGELOG.md

@@ -8,6 +8,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
 - A changelog
 - Support for embedding Python libraries at the category or puzzle level
+- Minimal PWA support to permit caching of currently-unlocked content
 - Embedded graph in scoreboard
 - Optional tracking of participant IDs
 - New `notices.html` file for sending broadcast messages to players

README.md

@@ -133,6 +133,18 @@ We sometimes to set `teamids.txt` to a bunch of random 8-digit hex values:
 Remember that team IDs are essentially passwords.
 
 
+Enabling offline/PWA mode
+-------------------
+
+If the file `state/export_manifest` is found, the server will expose the 
+endpoint `/current_manifest.json?id=<teamId>`. This endpoint will return 
+a list of all files, including static theme content and JSON and content 
+for currently-unlocked puzzles. This is used by the native PWA 
+implementation and `Cache` button on the index page to cache all of the 
+content necessary to display currently-open puzzles while offline. 
+Grading will be unavailable while offline. Some puzzles may not function 
+as expected while offline. A valid team ID must be provided.
+
 Mothball Directory
 ==================
 

src/handlers.go

@@ -8,6 +8,9 @@ import (
 	"log"
 	"net/http"
 	"os"
+	"path"
+	"path/filepath"
+	"regexp"
 	"strconv"
 	"strings"
 )
@@ -247,6 +250,65 @@ func (ctx *Instance) staticHandler(w http.ResponseWriter, req *http.Request) {
 	http.ServeContent(w, req, path, d.ModTime(), f)
 }
 
+func (ctx *Instance) manifestHandler(w http.ResponseWriter, req *http.Request) {
+	if !ctx.Runtime.export_manifest {
+		http.Error(w, "Endpoint disabled", http.StatusForbidden)
+		return
+	}
+
+	teamId := req.FormValue("id")
+	if _, err := ctx.TeamName(teamId); err != nil {
+		http.Error(w, "Must provide a valid team ID", http.StatusUnauthorized)
+		return
+	}
+
+	if req.Method == http.MethodHead {
+		w.WriteHeader(http.StatusOK)
+		return
+	}
+
+	manifest := make([]string, 0)
+	manifest = append(manifest, "puzzles.json")
+	manifest = append(manifest, "points.json")
+
+	// Pack up the theme files
+	theme_root_re := regexp.MustCompile(fmt.Sprintf("^%s/", ctx.ThemeDir))
+	filepath.Walk(ctx.ThemeDir, func(path string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+
+		if !info.IsDir() { // Only package up files
+			localized_path := theme_root_re.ReplaceAllLiteralString(path, "")
+			manifest = append(manifest, localized_path)
+		}
+		return nil
+	})
+
+	// Package up files for currently-unlocked puzzles in categories
+	for category_name, category := range ctx.categories {
+		if _, ok := ctx.MaxPointsUnlocked[category_name]; ok { // Check that the category is actually unlocked. This should never fail, probably
+			for _, file := range category.zf.File {
+				parts := strings.Split(file.Name, "/")
+
+				if parts[0] == "content" { // Only pick up content files, not thing like map.txt
+					for _, puzzlemap := range category.puzzlemap { // Figure out which puzzles are currently unlocked
+						if puzzlemap.Path == parts[1] && puzzlemap.Points <= ctx.MaxPointsUnlocked[category_name] {
+
+							manifest = append(manifest, path.Join("content", category_name, path.Join(parts[1:]...)))
+							break
+						}
+					}
+				}
+			}
+		}
+	}
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(http.StatusOK)
+	manifest_json, _ := json.Marshal(manifest)
+	w.Write(manifest_json)
+}
+
 type FurtiveResponseWriter struct {
 	w          http.ResponseWriter
 	statusCode *int
@@ -289,4 +351,5 @@ func (ctx *Instance) BindHandlers() {
 	ctx.mux.HandleFunc(ctx.Base+"/content/", ctx.contentHandler)
 	ctx.mux.HandleFunc(ctx.Base+"/puzzles.json", ctx.puzzlesHandler)
 	ctx.mux.HandleFunc(ctx.Base+"/points.json", ctx.pointsHandler)
+	ctx.mux.HandleFunc(ctx.Base+"/current_manifest.json", ctx.manifestHandler)
 }

src/instance.go

@@ -15,6 +15,10 @@ import (
 	"time"
 )
 
+type RuntimeConfig struct {
+	export_manifest bool
+}
+
 type Instance struct {
 	Base            string
 	MothballDir     string
@@ -22,7 +26,10 @@ type Instance struct {
 	ThemeDir        string
 	AttemptInterval time.Duration
 
+	Runtime RuntimeConfig
+
 	categories        map[string]*Mothball
+	MaxPointsUnlocked map[string]int
 	update            chan bool
 	jPuzzleList       []byte
 	jPointsLog        []byte

src/maintenance.go

@@ -12,11 +12,6 @@ import (
 	"time"
 )
 
-type PuzzleMap struct {
-	Points int
-	Path   string
-}
-
 func (pm *PuzzleMap) MarshalJSON() ([]byte, error) {
 	if pm == nil {
 		return []byte("null"), nil
@@ -41,45 +36,29 @@ func (ctx *Instance) generatePuzzleList() {
 
 	ret := map[string][]PuzzleMap{}
 	for catName, mb := range ctx.categories {
-		mf, err := mb.Open("map.txt")
-		if err != nil {
-			// File isn't in there
-			continue
-		}
-		defer mf.Close()
-
-		pm := make([]PuzzleMap, 0, 30)
+		filtered_puzzlemap := make([]PuzzleMap, 0, 30)
 		completed := true
-		scanner := bufio.NewScanner(mf)
-		for scanner.Scan() {
-			line := scanner.Text()
 
-			var pointval int
-			var dir string
+		for _, pm := range mb.puzzlemap {
+			filtered_puzzlemap = append(filtered_puzzlemap, pm)
 
-			n, err := fmt.Sscanf(line, "%d %s", &pointval, &dir)
-			if err != nil {
-				log.Printf("Parsing map for %s: %v", catName, err)
-				continue
-			} else if n != 2 {
-				log.Printf("Parsing map for %s: short read", catName)
-				continue
-			}
-
-			pm = append(pm, PuzzleMap{pointval, dir})
-
-			if pointval > maxByCategory[catName] {
+			if pm.Points > maxByCategory[catName] {
 				completed = false
+				maxByCategory[catName] = pm.Points
 				break
 			}
 		}
+
 		if completed {
-			pm = append(pm, PuzzleMap{0, ""})
+			filtered_puzzlemap = append(filtered_puzzlemap, PuzzleMap{0, ""})
 		}
 
-		ret[catName] = pm
+		ret[catName] = filtered_puzzlemap
 	}
 
+	// Cache the unlocked points for use in other functions
+	ctx.MaxPointsUnlocked = maxByCategory
+
 	jpl, err := json.Marshal(ret)
 	if err != nil {
 		log.Printf("Marshalling puzzles.js: %v", err)
@@ -124,6 +103,9 @@ func (ctx *Instance) tidy() {
 	// Do they want to reset everything?
 	ctx.MaybeInitialize()
 
+	// Check set config
+	ctx.UpdateConfig()
+
 	// Refresh all current categories
 	for categoryName, mb := range ctx.categories {
 		if err := mb.Refresh(); err != nil {
@@ -286,6 +268,20 @@ func (ctx *Instance) isEnabled() bool {
 	return true
 }
 
+func (ctx *Instance) UpdateConfig() {
+	// Handle export manifest
+	if _, err := os.Stat(ctx.StatePath("export_manifest")); err == nil {
+		if !ctx.Runtime.export_manifest {
+			log.Print("Enabling manifest export")
+			ctx.Runtime.export_manifest = true
+		}
+	} else if ctx.Runtime.export_manifest {
+		log.Print("Disabling manifest export")
+		ctx.Runtime.export_manifest = false
+	}
+
+}
+
 // maintenance is the goroutine that runs a periodic maintenance task
 func (ctx *Instance) Maintenance(maintenanceInterval time.Duration) {
 	for {

src/mothball.go

@@ -2,17 +2,25 @@ package main
 
 import (
 	"archive/zip"
+	"bufio"
 	"fmt"
 	"io"
 	"io/ioutil"
+	"log"
 	"os"
 	"strings"
 	"time"
 )
 
+type PuzzleMap struct {
+	Points int
+	Path   string
+}
+
 type Mothball struct {
 	zf        *zip.ReadCloser
 	filename  string
+	puzzlemap []PuzzleMap
 	mtime     time.Time
 }
 
@@ -150,6 +158,35 @@ func (m *Mothball) Refresh() error {
 	m.zf = zf
 	m.mtime = mtime
 
+	mf, err := m.Open("map.txt")
+	if err != nil {
+		// File isn't in there
+	} else {
+		defer mf.Close()
+
+		pm := make([]PuzzleMap, 0, 30)
+		scanner := bufio.NewScanner(mf)
+
+		for scanner.Scan() {
+			line := scanner.Text()
+
+			var pointval int
+			var dir string
+
+			n, err := fmt.Sscanf(line, "%d %s", &pointval, &dir)
+			if err != nil {
+				log.Printf("Parsing map for %v", err)
+			} else if n != 2 {
+				log.Printf("Parsing map: short read")
+			}
+
+			pm = append(pm, PuzzleMap{pointval, dir})
+
+		}
+
+		m.puzzlemap = pm
+	}
+
 	return nil
 }
 

theme/basic.css

@@ -136,3 +136,7 @@ li[draggable] {
 [draggable].over {
   border: 1px white dashed;
 }
+
+#cacheButton.disabled {
+  display: none;
+}

theme/index.html

@@ -5,7 +5,9 @@
     <meta charset="utf-8">
     <meta name="viewport" content="width=device-width">
     <link rel="stylesheet" href="basic.css">
+    <script src="moth-pwa.js" type="text/javascript"></script>
     <script src="moth.js"></script>
+    <link rel="manifest" href="manifest.json">
   </head>
   <body>
     <h1 id="title">MOTH</h1>
@@ -32,6 +34,7 @@
       <ul>
         <li><a href="scoreboard.html">Scoreboard</a></li>
         <li><a href="logout.html">Sign Out</a></li>
+	<li id="cacheButton" class="disabled"><a href="#" onclick='fetchAll()' title="Cache am offline copy of current content">Cache</a></li>
       </ul>
     </nav>
   </body>

theme/manifest.json

@@ -0,0 +1,9 @@
+{
+  "name": "Monarch of the Hill",
+  "short_name": "MOTH",
+  "start_url": ".",
+  "display": "standalone",
+  "background_color": "#282a33",
+  "theme_color": "#ECB",
+  "description": "The MOTH CTF engine"
+}

theme/moth-pwa.js

@@ -0,0 +1,17 @@
+function pwa_init() {
+  if ('serviceWorker' in navigator) {
+    navigator.serviceWorker.register("./sw.js").then(function(reg) {
+    })
+    .catch(err => {
+      console.warn("Error while registering service worker", err)
+    })
+  } else {
+    console.log("Service workers not supported. Some offline functionality may not work")
+  }
+}
+
+if (document.readyState === "loading") {
+  document.addEventListener("DOMContentLoaded", pwa_init)
+} else {
+  pwa_init()
+}

theme/moth.js

@@ -88,6 +88,7 @@ function renderPuzzles(obj) {
   container.appendChild(puzzlesElement)
 }
 
+
 function heartbeat(teamId, participantId) {
   let noticesUrl = new URL("notices.html", window.location)
   fetch(noticesUrl)
@@ -137,6 +138,90 @@ function showPuzzles(teamId, participantId) {
   document.getElementById("puzzles").appendChild(spinner)
   heartbeat(teamId, participantId)
   setInterval(e => { heartbeat(teamId) }, 40000)
+  drawCacheButton(teamId)
+}
+
+function drawCacheButton(teamId) {
+  let cacher = document.querySelector("#cacheButton")
+
+  function updateCacheButton() {
+    let headers = new Headers()
+    headers.append("pragma", "no-cache")
+    headers.append("cache-control", "no-cache")
+    let url = new URL("current_manifest.json", window.location)
+    url.searchParams.set("id", teamId)
+    fetch(url, {method: "HEAD", headers: headers})
+      .then( resp => {
+        if (resp.ok) {
+	  cacher.classList.remove("disabled")
+        } else {
+	  cacher.classList.add("disabled")
+        }
+      })
+      .catch(ex => {
+	  cacher.classList.add("disabled")
+      })
+  }
+
+  setInterval (updateCacheButton , 30000)
+  updateCacheButton()
+}
+
+async function fetchAll() {
+  let teamId = sessionStorage.getItem("id")
+  let headers = new Headers()
+  headers.append("pragma", "no-cache")
+  headers.append("cache-control", "no-cache")
+  requests = []
+  let url = new URL("current_manifest.json", window.location)
+  url.searchParams.set("id", teamId)
+
+  toast("Caching all currently-open content")
+  requests.push( fetch(url, {headers: headers})
+   .then( resp => {
+    if (resp.ok) {
+      resp.json()
+       .then(contents => {
+        console.log("Processing manifest")
+        for (let resource of contents) {
+          if (resource == "puzzles.json") {
+            continue
+          }
+          fetch(resource)
+           .then(e => {
+             console.log("Fetched " + resource)
+          })
+        }
+      })
+   }
+  }))
+
+  let resp = await fetch("puzzles.json?id=" + teamId, {headers: headers})
+	
+  if (resp.ok) {
+    let categories = await resp.json()
+    let cat_names = Object.keys(categories)
+    cat_names.sort()
+    for (let cat_name of cat_names) {
+      if (cat_name.startsWith("__")) {
+        // Skip metadata
+        continue
+      }
+      let puzzles = categories[cat_name]
+      for (let puzzle of puzzles) {
+	let url = new URL("puzzle.html", window.location)
+	url.searchParams.set("cat", cat_name)
+	url.searchParams.set("points", puzzle[0])
+	url.searchParams.set("pid", puzzle[1])
+        requests.push( fetch(url)
+         .then(e => {
+          console.log("Fetched " + url)
+        }))
+      }
+    }
+  }
+  await Promise.all(requests)
+  toast("Done caching content")
 }
 
 function login(e) {
@@ -191,7 +276,8 @@ function init() {
 }
 
 if (document.readyState === "loading") {
-  document.addEventListener("DOMContentLoaded", init);
+  document.addEventListener("DOMContentLoaded", init)
 } else {
-  init();
+  init()
 }
+

theme/puzzle.html

@@ -5,6 +5,7 @@
     <link rel="stylesheet" href="basic.css">
     <meta name="viewport" content="width=device-width">
     <meta charset="utf-8">
+    <script src="moth-pwa.js"></script>
     <script src="puzzle.js"></script>
     <script>
     

theme/scoreboard.html

@@ -4,6 +4,7 @@
     <title>Scoreboard</title>
     <link rel="stylesheet" href="basic.css">
     <meta name="viewport" content="width=device-width">
+    <script src="moth-pwa.js"></script>
     <script src="moment.min.js" async></script>
     <script src="Chart.min.js" async></script>
     <script src="scoreboard.js" async></script>

theme/sw.js

@@ -0,0 +1,49 @@
+var cacheName =  "moth:v1"
+var content = [
+  "index.html",
+  "basic.css",
+  "puzzle.js",
+  "puzzle.html",
+  "scoreboard.html",
+  "moth.js",
+  "sw.js",
+  "points.json",
+]
+
+self.addEventListener("install", function(e) {
+  e.waitUntil(
+    caches.open(cacheName).then(function(cache) {
+      return cache.addAll(content).then(
+        function() {
+          self.skipWaiting()
+        })
+    })
+  )
+})
+
+/* Attempt to fetch live resources, first, then fall back to cache */
+self.addEventListener('fetch', function(event) {
+  let cache_used = false
+
+  event.respondWith(
+    fetch(event.request)
+     .catch(function(evt) {
+      //console.log("Falling back to cache for " + event.request.url)
+      cache_used = true
+      return caches.match(event.request, {ignoreSearch: true})
+    }).then(function(res) {
+      if (res && res.ok) {
+        let res_clone = res.clone()
+	if (! cache_used && event.request.method == "GET" ) {
+          caches.open(cacheName).then(function(cache) {
+            cache.put(event.request, res_clone)
+            //console.log("Storing " + event.request.url + " in cache")
+          })
+	} 
+        return res
+      } else {
+        console.log("Failed to retrieve resource")
+      }
+    })
+  )
+})