commit 39cea7b77c3d8a5f2596441c306a7270f4894ebc
Author: Carl Pearson <me@carlpearson.net>
Date:   Mon Dec 30 05:36:42 2024 -0700

    Initial commit

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..fef2a97
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+subreddits
+go.sum
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..13c02a6
--- /dev/null
+++ b/README.md
@@ -0,0 +1,9 @@
+# reimager for Reddit
+
+Download images from reddit.
+
+```bash
+go mod tidy
+
+go run main.go
+```
\ No newline at end of file
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..93e33db
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,8 @@
+module github.com/cwpearson/reddit-images
+
+go 1.23.0
+
+require (
+	github.com/gabriel-vasile/mimetype v1.4.7 // indirect
+	golang.org/x/net v0.31.0 // indirect
+)
diff --git a/main.go b/main.go
new file mode 100644
index 0000000..e130060
--- /dev/null
+++ b/main.go
@@ -0,0 +1,34 @@
+package main
+
+import (
+	"log"
+	"time"
+
+	"github.com/cwpearson/reddit-images/rate_limit"
+	"github.com/cwpearson/reddit-images/reddit"
+)
+
+func main() {
+
+	subreddits := []string{
+		"pics",
+		"oldschoolcool",
+		"thewaywewere",
+		"MilitaryPorn",
+		"EarthPorn",
+	}
+
+	rl := rate_limit.NewRateLimit()
+
+	for {
+		for _, subreddit := range subreddits {
+			r := reddit.NewReddit(rl, subreddit)
+			r.Get()
+		}
+
+		when := time.Now().Add(time.Minute * time.Duration(30))
+		log.Println("sleep until", when)
+		time.Sleep(time.Until(when))
+	}
+
+}
diff --git a/rate_limit/rate_limit.go b/rate_limit/rate_limit.go
new file mode 100644
index 0000000..f1cd410
--- /dev/null
+++ b/rate_limit/rate_limit.go
@@ -0,0 +1,124 @@
+package rate_limit
+
+import (
+	"fmt"
+	"io"
+	"log"
+	"net/http"
+	"strconv"
+	"time"
+)
+
+type RateLimit struct {
+	client    *http.Client
+	used      int
+	remaining int
+	reset     time.Time
+}
+
+func getFutureTime(seconds int) time.Time {
+	return time.Now().Add(time.Duration(seconds) * time.Second)
+}
+
+func sleepUntil(when time.Time) {
+	now := time.Now()
+	if now.After(when) {
+		return
+	}
+	time.Sleep(when.Sub(now))
+}
+
+func NewRateLimit() *RateLimit {
+	return &RateLimit{
+		client:    &http.Client{},
+		remaining: 100,
+		reset:     time.Now(),
+	}
+}
+
+func (rl *RateLimit) UpdateUsed(used string) {
+	val, err := strconv.ParseFloat(used, 64)
+	if err == nil {
+		rl.used = int(val)
+		log.Println("used ->", rl.used)
+	}
+}
+
+func (rl *RateLimit) UpdateRemaining(used string) {
+	val, err := strconv.ParseFloat(used, 64)
+	if err == nil {
+		rl.remaining = int(val)
+		log.Println("remaining ->", rl.remaining)
+	}
+}
+
+func (rl *RateLimit) UpdateReset(used string) {
+	val, err := strconv.ParseFloat(used, 64)
+	if err == nil {
+		maybe := getFutureTime(int(val))
+		if rl.reset.Before(maybe) {
+			rl.reset = maybe
+			log.Println("reset ->", rl.reset)
+		}
+	}
+}
+
+// Get makes an HTTP GET request to the specified URL while respecting rate limits
+func (rl *RateLimit) Get(url string, accept string) ([]byte, error) {
+	if rl.remaining <= 0 {
+		log.Println("no requests remaining, sleep until", rl.reset)
+		sleepUntil(rl.reset)
+	}
+
+	// Create new request
+	log.Println("GET", url)
+	req, err := http.NewRequest("GET", url, nil)
+	if err != nil {
+		return nil, fmt.Errorf("failed to make request: %w", err)
+	}
+
+	// Add any required headers
+	req.Header.Add("User-Agent", "linux:reddit-images:0.1")
+	if accept != "" {
+		req.Header.Add("Accept", accept)
+	}
+
+	// Make the request
+	resp, err := rl.client.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("failed to make request: %w", err)
+	}
+	defer resp.Body.Close()
+
+	// parse rate limit
+	used := resp.Header.Get("X-Ratelimit-Used")
+	remaining := resp.Header.Get("X-Ratelimit-Remaining")
+	reset := resp.Header.Get("X-Ratelimit-Reset")
+	// fmt.Printf("User Limit: %s\n", used)
+	// fmt.Printf("Remaining: %s\n", remaining)
+	// fmt.Printf("Reset: %s\n", reset)
+	rl.UpdateUsed(used)
+	rl.UpdateRemaining(remaining)
+	rl.UpdateReset(reset)
+
+	if resp.StatusCode == http.StatusTooManyRequests {
+		rl.remaining = 0
+
+		// if the reset time is before now, just pick a while in the future for the next retry
+		if rl.reset.Before(time.Now()) {
+			rl.UpdateReset("450")
+		}
+		return nil, fmt.Errorf("request failed with 429")
+	}
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("request failed with status: %d", resp.StatusCode)
+	}
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read response body: %w", err)
+	}
+
+	return body, nil
+}
diff --git a/reddit/gallery.go b/reddit/gallery.go
new file mode 100644
index 0000000..75be61d
--- /dev/null
+++ b/reddit/gallery.go
@@ -0,0 +1,54 @@
+package reddit
+
+import (
+	"encoding/json"
+	"fmt"
+	"log"
+
+	"github.com/cwpearson/reddit-images/rate_limit"
+)
+
+type GListing struct {
+	Data GListingData `json:"data"`
+}
+
+type GListingData struct {
+	Children []GListingDataChild `json:"children"`
+}
+
+type GListingDataChild struct {
+	Data GListingDataChildData `json:"data"`
+}
+
+type GListingDataChildData struct {
+	MediaMetadata map[string]Metadata `json:"media_metadata"`
+}
+
+type Metadata struct {
+	Id       string `json:"id"`
+	Mimetype string `json:"m"`
+}
+
+func GalleryImageMetadata(rl *rate_limit.RateLimit, url string) ([]Metadata, error) {
+	jsonUrl := fmt.Sprintf("%s.json?raw_json=1", url)
+	log.Printf("gallery url: %s -> %s", url, jsonUrl)
+
+	content, err := rl.Get(jsonUrl, "")
+	if err != nil {
+		return nil, err
+	}
+
+	var data []GListing
+	err = json.Unmarshal(content, &data)
+	if err != nil {
+		return nil, err
+	}
+
+	res := []Metadata{}
+
+	for _, val := range data[0].Data.Children[0].Data.MediaMetadata {
+		res = append(res, val)
+	}
+
+	return res, nil
+}
diff --git a/reddit/reddit.go b/reddit/reddit.go
new file mode 100644
index 0000000..02f6f05
--- /dev/null
+++ b/reddit/reddit.go
@@ -0,0 +1,249 @@
+package reddit
+
+import (
+	"encoding/json"
+	"fmt"
+	"log"
+	"net/url"
+	"os"
+	"path/filepath"
+	"strings"
+	"time"
+
+	"github.com/cwpearson/reddit-images/rate_limit"
+	"github.com/gabriel-vasile/mimetype"
+)
+
+// Response represents the outer JSON structure
+type Response struct {
+	Data ListingData `json:"data"`
+}
+
+// ListingData represents the data field containing children
+type ListingData struct {
+	After    string  `json:"after"`
+	Children []Child `json:"children"`
+}
+
+// Child represents each item in the children array
+type Child struct {
+	Kind string    `json:"kind"`
+	Data ChildData `json:"data"`
+}
+
+// ChildData represents the nested data in each child
+type ChildData struct {
+	Title               string  `json:"title"`
+	Author              string  `json:"author"`
+	URLOverriddenByDest string  `json:"url_overridden_by_dest"`
+	URL                 string  `json:"url"`
+	Created             float64 `json:"created"`
+	Id                  string  `json:"id"`
+}
+
+type Reddit struct {
+	subreddit string
+	retries   int
+	rl        *rate_limit.RateLimit
+}
+
+func NewReddit(rl *rate_limit.RateLimit, subreddit string) *Reddit {
+	return &Reddit{
+		subreddit: subreddit,
+		retries:   3,
+		rl:        rl,
+	}
+}
+
+// returns children, after, error
+func (r *Reddit) Next(after string) ([]ChildData, string, error) {
+
+	baseURL := fmt.Sprintf("https://reddit.com/r/%s/hot.json", r.subreddit)
+
+	u, err := url.Parse(baseURL)
+	if err != nil {
+		panic(err)
+	}
+
+	// Create query parameters
+	params := url.Values{}
+	params.Add("raw_json", "1")
+	params.Add("limit", "100")
+	if after != "" {
+		params.Add("after", after)
+	}
+
+	// Add the query parameters to the URL
+	u.RawQuery = params.Encode()
+
+	var body []byte
+	for try := 0; try < r.retries; try++ {
+		body, err = r.rl.Get(u.String(), "")
+		if err != nil {
+			fmt.Printf("Error getting subreddit: %v\n", err)
+			body = nil
+			time.Sleep(time.Second * time.Duration(5))
+			continue
+		}
+		break
+	}
+	if body == nil {
+		return nil, "", fmt.Errorf("retries exceeded")
+	}
+	response := Response{}
+	err = json.Unmarshal(body, &response)
+	if err != nil {
+		return nil, "", err
+	}
+
+	res := []ChildData{}
+	for _, c := range response.Data.Children {
+		if c.Kind == "t3" { // link
+			res = append(res, c.Data)
+		}
+	}
+	return res, response.Data.After, nil
+}
+
+func getImage(rl *rate_limit.RateLimit, url, outDir, stem string) error {
+	contents, err := rl.Get(url, "image/*")
+	if err != nil {
+		return err
+	}
+	mtype := mimetype.Detect(contents)
+	name := stem + mtype.Extension()
+	outPath := filepath.Join(outDir, name)
+	log.Println("write", outPath)
+	return os.WriteFile(outPath, contents, 0644)
+}
+
+func (r *Reddit) Get() {
+	var children []ChildData
+	var err error
+
+	outDir := filepath.Join("subreddits", r.subreddit)
+	err = os.MkdirAll(outDir, 0755)
+	if err != nil && !os.IsExist(err) {
+		log.Println("ERROR: couldn't create out directory", outDir)
+		return
+	}
+
+	// load existing names
+	existing := map[string]struct{}{}
+	entries, err := os.ReadDir(outDir)
+	if err != nil {
+		log.Println("ERROR: couldn't read directory", outDir)
+		return
+	}
+	for _, entry := range entries {
+		if entry.IsDir() {
+			continue
+		}
+		filename := entry.Name()
+		nameWithoutSuffix := strings.TrimSuffix(filename, filepath.Ext(filename))
+		existing[nameWithoutSuffix] = struct{}{}
+	}
+
+	children, _, err = r.Next("")
+	if err != nil {
+		log.Println("ERROR: Next error:", err)
+		return
+	}
+
+	for _, child := range children {
+		log.Println("Title:", child.Title)
+		shortTitle := child.Title
+		if len(shortTitle) > 32 {
+			shortTitle = shortTitle[0:32]
+		}
+		shortTitle = sanitizeFilename(shortTitle)
+
+		if strings.Contains(child.URLOverriddenByDest, "www.reddit.com/gallery") {
+
+			metas, err := GalleryImageMetadata(r.rl, child.URLOverriddenByDest)
+			if err != nil {
+				log.Println("ERROR: Gallery handling error:", err)
+				continue
+			}
+
+			log.Println("Gallery metas:", metas)
+
+			for mi, meta := range metas {
+				parts := strings.Split(meta.Mimetype, "/")
+				if len(parts) == 2 {
+					imgUrl := fmt.Sprintf("https://i.redd.it/%s.%s", meta.Id, parts[1])
+
+					stem := fmt.Sprintf("%d_%s_%d_%s", int64(child.Created), shortTitle, mi, meta.Id)
+
+					if _, ok := existing[stem]; ok {
+						log.Println(stem, "already downloaded")
+						continue
+					}
+
+					err := getImage(r.rl, imgUrl, outDir, stem)
+					if err != nil {
+						log.Println("ERROR: getImage:", err)
+						continue
+					}
+					existing[stem] = struct{}{}
+				}
+			}
+
+			continue
+		} else {
+
+			stem := fmt.Sprintf("%d_%s_%s", int64(child.Created), shortTitle, child.Id)
+
+			if _, ok := existing[stem]; ok {
+				log.Println(stem, "already downloaded")
+				continue
+			}
+
+			err := getImage(r.rl, child.URLOverriddenByDest, outDir, stem)
+			if err != nil {
+				log.Println("ERROR: getImage:", err)
+				continue
+			}
+			existing[stem] = struct{}{}
+		}
+	}
+}
+
+func sanitizeFilename(input string) string {
+	// Replace path separators and problematic characters
+	replacer := strings.NewReplacer(
+		"/", "",
+		"\\", "",
+		":", "",
+		"*", "",
+		"?", "",
+		"\"", "",
+		"<", "",
+		">", "",
+		"|", "",
+		",", "",
+		";", "",
+		"\x00", "", // null byte
+		" ", "-", // replace spaces with hyphens
+	)
+	cleaned := replacer.Replace(input)
+
+	// Remove non-ASCII characters
+	var result strings.Builder
+	for _, r := range cleaned {
+		if r < 128 { // Keep only ASCII characters
+			result.WriteRune(r)
+		}
+	}
+	cleaned = result.String()
+
+	// Trim spaces (though they should already be replaced with hyphens)
+	cleaned = strings.TrimSpace(cleaned)
+
+	// If the filename becomes empty after cleaning, provide a default
+	if cleaned == "" {
+		return "unnamed_file"
+	}
+
+	return cleaned
+}