From 7e71d0cc7aa8ddca17b257c829b4bde5974454a6 Mon Sep 17 00:00:00 2001
From: Farhan Khan <farhan@farhan.codes>
Date: Mon, 1 Feb 2021 00:28:20 +0000
Subject: [PATCH] Installed recent requests structure to prevent repeat
 requests Default size is 5 Only targets posts, not users

---
 Makefile     |  4 ++--
 fedilogue.go |  5 +----
 fifo.go      | 45 +++++++++++++++++++++++++++++++++++++++++++++
 headers.go   |  1 +
 instance.go  |  6 +++++-
 retrieve.go  | 23 ++++++++++++++++-------
 6 files changed, 70 insertions(+), 14 deletions(-)
 create mode 100644 fifo.go

diff --git a/Makefile b/Makefile
index 9ea23a0..ee2f26c 100644
--- a/Makefile
+++ b/Makefile
@@ -1,5 +1,5 @@
-FEDILOGUE_GOFILES = fedilogue.go ctl.go headers.go instance.go poll.go stream.go web.go db.go config.go oauth.go retrieve.go log.go
-FEDICTL_GOFILES = fedictl.go headers.go log.go
+FEDILOGUE_GOFILES = fedilogue.go ctl.go headers.go instance.go poll.go stream.go web.go db.go config.go oauth.go retrieve.go log.go fifo.go
+FEDICTL_GOFILES = fedictl.go headers.go log.go fifo.go
 
 build:
 	go build -o fedilogue $(FEDILOGUE_GOFILES) 
diff --git a/fedilogue.go b/fedilogue.go
index 3eb762d..9599322 100644
--- a/fedilogue.go
+++ b/fedilogue.go
@@ -43,13 +43,10 @@ func main() {
 
 	for _, endpoint := range settings.Autostart {
 		logInfo.Print("Autostarting " + endpoint)
-		ri_mutex.Lock()
-		_, exists := runninginstances[endpoint]
+		_, exists := GetRunner(endpoint)
 		if exists == false {
-			runninginstances[endpoint] = RunningInstance{}
 			go StartInstance(endpoint)
 		}
-		ri_mutex.Unlock()
 	}
 
 	go startctl()
diff --git a/fifo.go b/fifo.go
new file mode 100644
index 0000000..5290ed5
--- /dev/null
+++ b/fifo.go
@@ -0,0 +1,45 @@
+package main
+
+import (
+	"sync"
+)
+
+type Fifo struct {
+    slice []string
+	mu sync.Mutex
+	size int
+}
+
+func newfifo(size int) *Fifo {
+    q := Fifo{}
+    q.slice = make([]string, 0)
+	q.size = size
+    return &q
+}
+func (q *Fifo) Add(v string) int {
+	q.mu.Lock()
+	i := q.Contains(v)
+	if i == -1 {
+		if len(q.slice) >= q.size {
+			q.DeleteFirst()
+		}
+		q.slice = append(q.slice, v)
+	}
+	q.mu.Unlock()
+	return i
+}
+
+func (q *Fifo) Contains(v string) int {
+	for i, val := range q.slice {
+		if val == v {
+			return i
+		}
+	}
+	return -1
+}
+
+func (q *Fifo) DeleteFirst() string {
+    a := q.slice[0]
+    q.slice = q.slice[1:]
+    return a
+}
diff --git a/headers.go b/headers.go
index e2e8ac2..376fb44 100644
--- a/headers.go
+++ b/headers.go
@@ -60,6 +60,7 @@ type RunningInstance struct {
 	client        http.Client
 	client_id     string
 	client_secret string
+	recenturis    *Fifo
 }
 
 type NodeInfoSoftware struct {
diff --git a/instance.go b/instance.go
index caaf77b..50ed1bd 100644
--- a/instance.go
+++ b/instance.go
@@ -58,10 +58,12 @@ func BuildClient(endpoint string) http.Client {
 func GetRunner(endpoint string) (RunningInstance, bool) {
 	ri_mutex.Lock()
 	o, exists := runninginstances[endpoint]
+
 	if exists == false {
-		o := RunningInstance{}
+		o = RunningInstance{}
 		o.client = BuildClient(endpoint)
 		o.Status = KEEPALIVE
+		o.recenturis = newfifo(5)
 		runninginstances[endpoint] = o
 	}
 	ri_mutex.Unlock()
@@ -166,11 +168,13 @@ func CheckInstance(newinstance string, callerEndpoint string) {
 			return
 		}
 
+		// Going forward, this might be merged into GetRunner
 		ri_mutex.Lock()
 		o, exists := runninginstances[newinstance]
 		if exists == false || o.Status == KEEPALIVE {
 			m := RunningInstance{}
 			m.client = BuildClient(newinstance)
+			m.recenturis = newfifo(5)
 			runninginstances[newinstance] = m
 			go StartInstance(newinstance)
 		}
diff --git a/retrieve.go b/retrieve.go
index 485f958..8af5594 100644
--- a/retrieve.go
+++ b/retrieve.go
@@ -72,25 +72,34 @@ type PostJson struct {
 
 func check_post(uri string) (PostJson, error) {
 	var postjson PostJson
+
+	// Ignore banned
 	for _, banned := range settings.Banned {
 		if strings.Index(uri, "https://"+banned+"/") == 0 {
 			return postjson, errors.New("Banned instance")
 		}
 	}
 
+	// Ignore invalid URIs
+	endslash := strings.Index(uri[8:], "/")
+	if endslash == -1 {
+		return postjson, errors.New("Invalid URI " + uri)
+	}
+	postjson.instance = uri[8 : endslash+8]
+
+	o, _ := GetRunner(postjson.instance)
+
+	// Check if there were any recent requests on this
+	if o.recenturis.Add(uri) != -1 {
+			return postjson, errors.New("Recently requested within local cache")
+	}
+
 	selectRet := pool.QueryRow(context.Background(), "SELECT id, inReplyTo, published, summary, content, normalized, attributedto, posthash, received_at FROM posts WHERE id = $1", uri)
 	err := selectRet.Scan(&postjson.ID, &postjson.InReplyTo, &postjson.Published, &postjson.Summary, &postjson.Content, &postjson.normalized, &postjson.AttributedTo, &postjson.posthash, &postjson.receivedAt)
 	if err == nil {
 		return postjson, nil
 	}
 
-	endslash := strings.Index(uri[8:], "/")
-	if endslash == -1 {
-		return postjson, errors.New("Invalid URI " + uri)
-	}
-	postjson.instance = uri[8 : endslash+8]
-
-	o, _ := GetRunner(postjson.instance)
 	req, _ := http.NewRequest("GET", uri, nil)
 	req.Header.Set("User-Agent", "Tusky")
 	req.Header.Add("Accept", "application/ld+json")