initial commit

.gitignore

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+# Compiled Object files, Static and Dynamic libs (Shared Objects)
+*.o
+*.a
+*.so
+
+# Folders
+_obj
+_test
+
+# Architecture specific extensions/prefixes
+*.[568vq]
+[568vq].out
+
+*.cgo1.go
+*.cgo2.c
+_cgo_defun.c
+_cgo_gotypes.go
+_cgo_export.*
+
+_testmain.go
+
+*.exe
+*.test
+*.prof
+
+# Output of the go coverage tool, specifically when used with LiteIDE
+*.out
+
+config.ini

LICENSE

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+MIT License
+
+Copyright (c) 2016 Sebastian Winkler
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

main.go

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+package main
+
+import (
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"net/url"
+	"os"
+	"path"
+	"path/filepath"
+	"regexp"
+
+	"strconv"
+	"strings"
+
+	"github.com/bwmarrin/discordgo"
+	"github.com/mvdan/xurls"
+	"gopkg.in/ini.v1"
+)
+
+var (
+	Email            string
+	Password         string
+	Token            string
+	ChannelWhitelist map[string]string
+	BaseDownloadPath string
+	RegexpUrlTwitter *regexp.Regexp
+	RegexpUrlTistory *regexp.Regexp
+)
+
+func main() {
+	var err error
+	cfg, err := ini.Load("config.ini")
+	if err != nil {
+		fmt.Println("unable to read config file", err)
+		cfg = ini.Empty()
+	}
+
+	if !cfg.Section("auth").HasKey("email") ||
+		!cfg.Section("auth").HasKey("password") {
+		cfg.Section("auth").NewKey("email", "your@email.com")
+		cfg.Section("auth").NewKey("password", "yourpassword")
+		cfg.Section("channels").NewKey("channelid1", "C:\\full\\path\\1")
+		cfg.Section("channels").NewKey("channelid2", "C:\\full\\path\\2")
+		cfg.Section("channels").NewKey("channelid3", "C:\\full\\path\\3")
+		err = cfg.SaveTo("config.ini")
+
+		if err != nil {
+			fmt.Println("unable to write config file", err)
+			return
+		}
+		fmt.Println("Wrote config file, please fill out and restart the program")
+		return
+	}
+
+	ChannelWhitelist = cfg.Section("channels").KeysHash()
+
+	RegexpUrlTwitter, err = regexp.Compile(
+		`^http(s?):\/\/pbs\.twimg\.com\/media\/[a-zA-Z]+\.jpg((\:[a-z]+)?)$`)
+	if err != nil {
+		fmt.Println("Regexp error", err)
+		return
+	}
+	RegexpUrlTistory, err = regexp.Compile(
+		`^http(s?):\/\/[a-z0-9]+\.uf\.tistory\.com\/(image|original)\/[A-Z0-9]+$`)
+	if err != nil {
+		fmt.Println("Regexp error", err)
+		return
+	}
+
+	dg, err := discordgo.New(
+		cfg.Section("auth").Key("email").String(),
+		cfg.Section("auth").Key("password").String())
+	if err != nil {
+		fmt.Println("error creating Discord session,", err)
+		return
+	}
+
+	dg.AddHandler(messageCreate)
+
+	err = dg.Open()
+	if err != nil {
+		fmt.Println("error opening connection,", err)
+		return
+	}
+
+	fmt.Println("Client is now connected. Press CTRL-C to exit.")
+	// keep program running until CTRL-C is pressed.
+	<-make(chan struct{})
+	return
+}
+
+func messageCreate(s *discordgo.Session, m *discordgo.MessageCreate) {
+	if folderName, ok := ChannelWhitelist[m.ChannelID]; ok {
+		downloadPath := folderName
+		for _, iAttachment := range m.Attachments {
+			downloadFromUrl(iAttachment.URL, iAttachment.Filename, downloadPath)
+		}
+		foundUrls := xurls.Strict.FindAllString(m.Content, -1)
+		for _, iFoundUrl := range foundUrls {
+			// Twitter url?
+			if RegexpUrlTwitter.MatchString(iFoundUrl) {
+				err := handleTwitterUrl(iFoundUrl, downloadPath)
+				if err != nil {
+					fmt.Println("Twitter url failed,", iFoundUrl, ",", err)
+					continue
+				}
+				// Tistory url?
+			} else if RegexpUrlTistory.MatchString(iFoundUrl) {
+				err := handleTistoryUrl(iFoundUrl, downloadPath)
+				if err != nil {
+					fmt.Println("Tistory url failed,", iFoundUrl, ",", err)
+					continue
+				}
+			} else {
+				// Any other url
+				downloadFromUrl(iFoundUrl,
+					getContentDispositionFilename(iFoundUrl), downloadPath)
+			}
+		}
+	}
+}
+
+func handleTwitterUrl(url string, folder string) error {
+	parts := strings.Split(url, ":")
+	if len(parts) < 2 {
+		errors.New("unable to format twitter url")
+	} else {
+		downloadFromUrl("https:"+parts[1]+":orig", path.Base(parts[1]), folder)
+	}
+	return nil
+}
+
+func handleTistoryUrl(url string, folder string) error {
+	url = strings.Replace(url, "/image/", "/original/", -1)
+	downloadFromUrl(url, getContentDispositionFilename(url), folder)
+	return nil
+}
+
+func getContentDispositionFilename(dUrl string) string {
+	resp, err := http.Head(dUrl)
+	if err != nil {
+		return path.Base(dUrl)
+	}
+	for key, iHeader := range resp.Header {
+		if key == "Content-Disposition" {
+			parts := strings.Split(iHeader[0], "\"")
+			if len(parts) == 3 {
+				filename, err := url.QueryUnescape(parts[1])
+				if err != nil {
+					return parts[1]
+				} else {
+					return filename
+				}
+			}
+		}
+	}
+	return path.Base(dUrl)
+}
+
+func downloadFromUrl(url string, filename string, path string) {
+	err := os.MkdirAll(path, 755)
+	if err != nil {
+		fmt.Println("Error while creating folder", path, "-", err)
+		return
+	}
+
+	completePath := path + string(os.PathSeparator) + filename
+	if _, err := os.Stat(completePath); err == nil {
+		tmpPath := completePath
+		i := 1
+		for {
+			completePath = tmpPath[0:len(tmpPath)-len(filepath.Ext(tmpPath))] +
+				"-" + strconv.Itoa(i) + filepath.Ext(tmpPath)
+			if _, err := os.Stat(completePath); os.IsNotExist(err) {
+				break
+			}
+			i = i + 1
+		}
+	}
+
+	response, err := http.Get(url)
+	if err != nil {
+		fmt.Println("Error while downloading", url, "-", err)
+		return
+	}
+	defer response.Body.Close()
+
+	bodyOfResp, err := ioutil.ReadAll(response.Body)
+	if err != nil {
+		fmt.Println("Could not read response", url, "-", err)
+		return
+	}
+	contentType := http.DetectContentType(bodyOfResp)
+	contentTypeParts := strings.Split(contentType, "/")
+	if contentTypeParts[0] != "image" {
+		fmt.Println("No image found", url)
+		return
+	}
+
+	err = ioutil.WriteFile(completePath, bodyOfResp, 0644)
+	if err != nil {
+		fmt.Println("Error while writing to disk", url, "-", err)
+		return
+	}
+
+	fmt.Printf("Downloaded url: %s to %s\n", url, completePath)
+}

readme.md

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+# discord-image-downloader-go
+
+This is a simple tool which downloads pictures posted in discord channels of your choice to a local folder. It handles various sources like twitter differently to make sure to download the best quality available. It is written in go and the code is very ugly.
+
+## How to use?
+When you run the tool for the first time it creates an `config.ini` file with example values. Edit these values and run the tool for a second time. It should connect to discords api and wait for new messages.
+
+### Where do I get the channel id?
+Open discord in your browser and go to the channel you want to monitor. In your adress bar should be an URL like `https://discordapp.com/channels/1234/5678`. The number after the last slash is the channel id, in this case `5678`.