yep good

.gitignore

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+dl
+dist*
+vendor

Gopkg.lock

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+# This file is autogenerated, do not edit; changes may be undone by the next 'dep ensure'.
+
+
+[[projects]]
+  digest = "1:6f9339c912bbdda81302633ad7e99a28dfa5a639c864061f1929510a9a64aa74"
+  name = "github.com/dustin/go-humanize"
+  packages = ["."]
+  pruneopts = "UT"
+  revision = "9f541cc9db5d55bce703bd99987c9d5cb8eea45e"
+  version = "v1.0.0"
+
+[solve-meta]
+  analyzer-name = "dep"
+  analyzer-version = 1
+  input-imports = ["github.com/dustin/go-humanize"]
+  solver-name = "gps-cdcl"
+  solver-version = 1

Gopkg.toml

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+# Gopkg.toml example
+#
+# Refer to https://golang.github.io/dep/docs/Gopkg.toml.html
+# for detailed Gopkg.toml documentation.
+#
+# required = ["github.com/user/thing/cmd/thing"]
+# ignored = ["github.com/user/project/pkgX", "bitbucket.org/user/project/pkgA/pkgY"]
+#
+# [[constraint]]
+#   name = "github.com/user/project"
+#   version = "1.0.0"
+#
+# [[constraint]]
+#   name = "github.com/user/project2"
+#   branch = "dev"
+#   source = "github.com/myfork/project2"
+#
+# [[override]]
+#   name = "github.com/x/y"
+#   version = "2.4.0"
+#
+# [prune]
+#   non-go = false
+#   go-tests = true
+#   unused-packages = true
+
+
+[[constraint]]
+  name = "github.com/dustin/go-humanize"
+  version = "1.0.0"
+
+[prune]
+  go-tests = true
+  unused-packages = true

LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2019 TJ Horner
+
+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.

Makefile

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+.PHONY: dist dist-win dist-macos dist-linux ensure-dist-dir build install uninstall
+
+GOBUILD=go build -ldflags="-s -w"
+INSTALLPATH=/usr/local/bin
+
+ensure-dist-dir:
+	@- mkdir -p dist
+
+dist-win: ensure-dist-dir
+	# Build for Windows x64
+	GOOS=windows GOARCH=amd64 $(GOBUILD) -o dist/e6dl-windows-amd64.exe *.go
+
+dist-macos: ensure-dist-dir
+	# Build for macOS x64
+	GOOS=darwin GOARCH=amd64 $(GOBUILD) -o dist/e6dl-darwin-amd64 *.go
+
+dist-linux: ensure-dist-dir
+	# Build for Linux x64
+	GOOS=linux GOARCH=amd64 $(GOBUILD) -o dist/e6dl-linux-amd64 *.go
+
+dist: dist-win dist-macos dist-linux
+
+build:
+	@- mkdir -p bin
+	$(GOBUILD) -o bin/e6dl *.go
+	@- chmod +x bin/e6dl
+
+install: build
+	mv bin/e6dl $(INSTALLPATH)/e6dl
+	@- rm -rf bin
+	@echo "e6dl was installed to $(INSTALLPATH)/e6dl. Run make uninstall to get rid of it, or just remove the binary yourself."
+
+uninstall:
+	rm $(INSTALLPATH)/e6dl

README.md

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+# e6dl
+
+This is a command line tool for downloading posts that match certain tags on e621 or e926.
+
+It does basically the same thing as [this tool](https://www.npmjs.com/package/e6dl) except it was written in Go and the output is a lot less pretty.
+
+I made this because I wanted to rewrite one of my previous projects in Go, so I decided to start with this one since it's a pretty small and simple command line tool.
+
+## Installing, Building, etc.
+
+See [here](https://github.com/tjhorner/nplcsv/blob/master/README.md) since it uses the same Makefile.
+
+## Usage
+
+```
+Usage of e6dl:
+  --concurrents int
+    	Maximum amount of concurrent downloads (default 5)
+  --limit int
+    	Maximum amount of posts to grab from e621 (default 10)
+  --out string
+    	The directory to write the downloaded posts to (default "dl")
+  --sfw
+    	Download posts from e926 instead of e621.
+  --tags string
+    	Tags to search for
+```

download.go

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+package main
+
+import (
+	"fmt"
+	"io/ioutil"
+	"path"
+	"strconv"
+	"strings"
+	"sync"
+
+	"github.com/dustin/go-humanize"
+)
+
+// BeginDownload is meant to be called as a goroutine and begins the post download process.
+func BeginDownload(posts *[]Post, saveDirectory *string, maxConcurrents *int) {
+	var wg sync.WaitGroup
+	var completed int
+
+	total := len(*posts)
+
+	// Distribute the posts based on the number of workers
+	ppw := len(*posts) / *maxConcurrents
+	mod := len(*posts) % *maxConcurrents
+
+	for i := 0; i < *maxConcurrents; i++ {
+		postsLower := i * ppw
+		postsUpper := i*ppw + ppw
+
+		if i == *maxConcurrents-1 {
+			// Give the last worker the remaining posts
+			// TODO: compensate it for labor
+			postsUpper += mod
+		}
+
+		wg.Add(1)
+		go work(i+1, (*posts)[postsLower:postsUpper], *saveDirectory, &completed, &total, &wg)
+	}
+
+	wg.Wait()
+}
+
+func work(wn int, posts []Post, directory string, completed *int, total *int, wg *sync.WaitGroup) {
+	defer wg.Done()
+
+	for _, post := range posts {
+		*completed++
+		fmt.Printf("[%d/%d] [w%d] Downloading post %d (%s)...\n", *completed, *total, wn, post.ID, humanize.Bytes(uint64(post.FileSize)))
+		downloadPost(&post, directory)
+	}
+}
+
+func downloadPost(post *Post, directory string) {
+	pathSliced := strings.Split(post.FileURL, ".")
+	extension := pathSliced[len(pathSliced)-1]
+
+	resp, err := HTTPGet(post.FileURL)
+	if err != nil {
+		fmt.Println("Unable to download, skipping...")
+		return
+	}
+	defer resp.Body.Close()
+
+	body, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		fmt.Println("Unable to read post response body, skipping...")
+		return
+	}
+
+	savePath := path.Join(directory, strconv.Itoa(post.ID)+"."+extension)
+
+	err = ioutil.WriteFile(savePath, body, 0755)
+	if err != nil {
+		fmt.Printf("Error: could not write to file: %v\n", err)
+		return
+	}
+}

e621.go

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+package main
+
+import (
+	"encoding/json"
+	"io/ioutil"
+	"net/http"
+	"strconv"
+)
+
+// Post represents an e621 post object returned by the e621 API.
+type Post struct {
+	ID             int            `json:"id"`
+	Tags           string         `json:"tags"`
+	LockedTags     bool           `json:"locked_tags"`
+	Description    string         `json:"description"`
+	CreatedAt      SerializedDate `json:"created_at"`
+	CreatorID      int            `json:"creator_id"`
+	Author         string         `json:"author"`
+	Change         int            `json:"change"`
+	Source         string         `json:"source"`
+	Score          int            `json:"score"`
+	FavoritesCount int            `json:"fav_count"`
+	MD5Hash        string         `json:"md5"`
+	FileSize       int            `json:"file_size"`
+	FileURL        string         `json:"file_url"`
+	FileExt        string         `json:"file_ext"`
+	PreviewURL     string         `json:"preview_url"`
+	PreviewHeight  int            `json:"preview_height"`
+	PreviewWidth   int            `json:"preview_width"`
+	Rating         string         `json:"rating"`
+	Status         string         `json:"status"`
+	Width          int            `json:"width"`
+	Height         int            `json:"height"`
+	HasComments    bool           `json:"has_comments"`
+	HasNotes       bool           `json:"has_notes"`
+	HasChildren    bool           `json:"has_children"`
+	Children       string         `json:"children"`
+	ParentID       int            `json:"parent_id"`
+	Artist         []string       `json:"artist"`
+	Sources        []string       `json:"sources"`
+}
+
+// SerializedDate represents a serialized date passed via JSON
+type SerializedDate struct {
+	JSONClass   string `json:"json_class"`
+	Seconds     int    `json:"s"`
+	Nanoseconds int    `json:"n"`
+}
+
+// GetPostsForTags gets a list of e621 Posts
+func GetPostsForTags(tags string, limit int, sfw bool) ([]Post, error) {
+	client := &http.Client{}
+
+	var domain string
+
+	if sfw {
+		domain = "e926.net"
+	} else {
+		domain = "e621.net"
+	}
+
+	req, _ := http.NewRequest("GET", "https://"+domain+"/post/index.json", nil)
+	req.Header.Set("User-Agent", "e6dl: go edition (@tjhorner on Telegram)")
+
+	qs := req.URL.Query()
+	qs.Add("tags", tags)
+	qs.Add("limit", strconv.Itoa(limit))
+
+	req.URL.RawQuery = qs.Encode()
+
+	resp, err := client.Do(req)
+	if err != nil {
+		return nil, err
+	}
+
+	defer resp.Body.Close()
+
+	body, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return nil, err
+	}
+
+	var posts []Post
+	json.Unmarshal(body, &posts)
+
+	return posts, nil
+}

main.go

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+package main
+
+import (
+	"flag"
+	"fmt"
+	"os"
+	"path"
+)
+
+func main() {
+	// define cmd line flags
+	tags := flag.String("tags", "", "Tags to search for")
+	maxConcurrents := flag.Int("concurrents", 5, "Maximum amount of concurrent downloads")
+	postLimit := flag.Int("limit", 10, "Maximum amount of posts to grab from e621")
+	saveDirectory := flag.String("out", "dl", "The directory to write the downloaded posts to")
+	sfw := flag.Bool("sfw", false, "Download posts from e926 instead of e621.")
+
+	flag.Parse()
+
+	fmt.Printf("Fetching posts for \"%v\" (limit %v)\n", *tags, *postLimit)
+
+	posts, err := GetPostsForTags(*tags, *postLimit, *sfw)
+	if err != nil {
+		fmt.Println(err)
+		os.Exit(1)
+	}
+
+	fmt.Printf("Found %d posts. Starting download with %d workers...\n\n", len(posts), *maxConcurrents)
+
+	cwd, _ := os.Getwd()
+	absSaveDir := path.Join(cwd, *saveDirectory)
+
+	err = os.MkdirAll(absSaveDir, 0755)
+	if err != nil {
+		fmt.Printf("Cannot create output directory (%s). Do you have the right permissions?\n", absSaveDir)
+		os.Exit(1)
+	}
+
+	BeginDownload(&posts, saveDirectory, maxConcurrents)
+
+	fmt.Printf("All done! %d posts downloaded and saved.\n", len(posts))
+}

util.go

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+package main
+
+import (
+	"net/http"
+)
+
+// HTTPGet is a helper function that automatically adds the
+// tool's UA to an HTTP GET request
+func HTTPGet(url string) (*http.Response, error) {
+	client := &http.Client{}
+
+	req, _ := http.NewRequest("GET", url, nil)
+	req.Header.Set("User-Agent", "e6dl: go edition (@tjhorner on Telegram)")
+
+	return client.Do(req)
+}