working v1

bridge/helper/helper.go

@@ -0,0 +1,287 @@
+package helper
+
+import (
+	"bytes"
+	"fmt"
+	"image/png"
+	"io"
+	"net/http"
+	"regexp"
+	"strings"
+	"time"
+	"unicode/utf8"
+
+	"golang.org/x/image/webp"
+
+	"github.com/42wim/matterbridge/bridge/config"
+	"github.com/gomarkdown/markdown"
+	"github.com/gomarkdown/markdown/html"
+	"github.com/gomarkdown/markdown/parser"
+	"github.com/sirupsen/logrus"
+)
+
+// DownloadFile downloads the given non-authenticated URL.
+func DownloadFile(url string) (*[]byte, error) {
+	return DownloadFileAuth(url, "")
+}
+
+// DownloadFileAuth downloads the given URL using the specified authentication token.
+func DownloadFileAuth(url string, auth string) (*[]byte, error) {
+	var buf bytes.Buffer
+	client := &http.Client{
+		Timeout: time.Second * 5,
+	}
+	req, err := http.NewRequest("GET", url, nil)
+	if auth != "" {
+		req.Header.Add("Authorization", auth)
+	}
+	if err != nil {
+		return nil, err
+	}
+	resp, err := client.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+	io.Copy(&buf, resp.Body)
+	data := buf.Bytes()
+	return &data, nil
+}
+
+// DownloadFileAuthRocket downloads the given URL using the specified Rocket user ID and authentication token.
+func DownloadFileAuthRocket(url, token, userID string) (*[]byte, error) {
+	var buf bytes.Buffer
+	client := &http.Client{
+		Timeout: time.Second * 5,
+	}
+	req, err := http.NewRequest("GET", url, nil)
+
+	req.Header.Add("X-Auth-Token", token)
+	req.Header.Add("X-User-Id", userID)
+
+	if err != nil {
+		return nil, err
+	}
+	resp, err := client.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+	_, err = io.Copy(&buf, resp.Body)
+	data := buf.Bytes()
+	return &data, err
+}
+
+// GetSubLines splits messages in newline-delimited lines. If maxLineLength is
+// specified as non-zero GetSubLines will also clip long lines to the maximum
+// length and insert a warning marker that the line was clipped.
+//
+// TODO: The current implementation has the inconvenient that it disregards
+// word boundaries when splitting but this is hard to solve without potentially
+// breaking formatting and other stylistic effects.
+func GetSubLines(message string, maxLineLength int, clippingMessage string) []string {
+	if clippingMessage == "" {
+		clippingMessage = " <clipped message>"
+	}
+
+	var lines []string
+	for _, line := range strings.Split(strings.TrimSpace(message), "\n") {
+		if line == "" {
+			// Prevent sending empty messages, so we'll skip this line
+			// if it has no content.
+			continue
+		}
+
+		if maxLineLength == 0 || len([]byte(line)) <= maxLineLength {
+			lines = append(lines, line)
+			continue
+		}
+
+		// !!! WARNING !!!
+		// Before touching the splitting logic below please ensure that you PROPERLY
+		// understand how strings, runes and range loops over strings work in Go.
+		// A good place to start is to read https://blog.golang.org/strings. :-)
+		var splitStart int
+		var startOfPreviousRune int
+		for i := range line {
+			if i-splitStart > maxLineLength-len([]byte(clippingMessage)) {
+				lines = append(lines, line[splitStart:startOfPreviousRune]+clippingMessage)
+				splitStart = startOfPreviousRune
+			}
+			startOfPreviousRune = i
+		}
+		// This last append is safe to do without looking at the remaining byte-length
+		// as we assume that the byte-length of the last rune will never exceed that of
+		// the byte-length of the clipping message.
+		lines = append(lines, line[splitStart:])
+	}
+	return lines
+}
+
+// HandleExtra manages the supplementary details stored inside a message's 'Extra' field map.
+func HandleExtra(msg *config.Message, general *config.Protocol) []config.Message {
+	extra := msg.Extra
+	rmsg := []config.Message{}
+	for _, f := range extra[config.EventFileFailureSize] {
+		fi := f.(config.FileInfo)
+		text := fmt.Sprintf("file %s too big to download (%#v > allowed size: %#v)", fi.Name, fi.Size, general.MediaDownloadSize)
+		rmsg = append(rmsg, config.Message{
+			Text:     text,
+			Username: "<system> ",
+			Channel:  msg.Channel,
+			Account:  msg.Account,
+		})
+	}
+	return rmsg
+}
+
+// GetAvatar constructs a URL for a given user-avatar if it is available in the cache.
+func GetAvatar(av map[string]string, userid string, general *config.Protocol) string {
+	if sha, ok := av[userid]; ok {
+		return general.MediaServerDownload + "/" + sha + "/" + userid + ".png"
+	}
+	return ""
+}
+
+// HandleDownloadSize checks a specified filename against the configured download blacklist
+// and checks a specified file-size against the configure limit.
+func HandleDownloadSize(logger *logrus.Entry, msg *config.Message, name string, size int64, general *config.Protocol) error {
+	// check blacklist here
+	for _, entry := range general.MediaDownloadBlackList {
+		if entry != "" {
+			re, err := regexp.Compile(entry)
+			if err != nil {
+				logger.Errorf("incorrect regexp %s for %s", entry, msg.Account)
+				continue
+			}
+			if re.MatchString(name) {
+				return fmt.Errorf("Matching blacklist %s. Not downloading %s", entry, name)
+			}
+		}
+	}
+	logger.Debugf("Trying to download %#v with size %#v", name, size)
+	if int(size) > general.MediaDownloadSize {
+		msg.Event = config.EventFileFailureSize
+		msg.Extra[msg.Event] = append(msg.Extra[msg.Event], config.FileInfo{
+			Name:    name,
+			Comment: msg.Text,
+			Size:    size,
+		})
+		return fmt.Errorf("File %#v to large to download (%#v). MediaDownloadSize is %#v", name, size, general.MediaDownloadSize)
+	}
+	return nil
+}
+
+// HandleDownloadData adds the data for a remote file into a Matterbridge gateway message.
+func HandleDownloadData(logger *logrus.Entry, msg *config.Message, name, comment, url string, data *[]byte, general *config.Protocol) {
+	HandleDownloadData2(logger, msg, name, "", comment, url, data, general)
+}
+
+// HandleDownloadData adds the data for a remote file into a Matterbridge gateway message.
+func HandleDownloadData2(logger *logrus.Entry, msg *config.Message, name, id, comment, url string, data *[]byte, general *config.Protocol) {
+	var avatar bool
+	logger.Debugf("Download OK %#v %#v", name, len(*data))
+	if msg.Event == config.EventAvatarDownload {
+		avatar = true
+	}
+	msg.Extra["file"] = append(msg.Extra["file"], config.FileInfo{
+		Name:     name,
+		Data:     data,
+		URL:      url,
+		Comment:  comment,
+		Avatar:   avatar,
+		NativeID: id,
+	})
+}
+
+var emptyLineMatcher = regexp.MustCompile("\n+")
+
+// RemoveEmptyNewLines collapses consecutive newline characters into a single one and
+// trims any preceding or trailing newline characters as well.
+func RemoveEmptyNewLines(msg string) string {
+	return emptyLineMatcher.ReplaceAllString(strings.Trim(msg, "\n"), "\n")
+}
+
+// ClipMessage trims a message to the specified length if it exceeds it and adds a warning
+// to the message in case it does so.
+func ClipMessage(text string, length int, clippingMessage string) string {
+	if clippingMessage == "" {
+		clippingMessage = " <clipped message>"
+	}
+
+	if len(text) > length {
+		text = text[:length-len(clippingMessage)]
+		for len(text) > 0 {
+			if r, _ := utf8.DecodeLastRuneInString(text); r == utf8.RuneError {
+				text = text[:len(text)-1]
+				// Note: DecodeLastRuneInString only returns the constant value "1" in
+				// case of an error. We do not yet know whether the last rune is now
+				// actually valid. Example: "€" is 0xE2 0x82 0xAC. If we happen to split
+				// the string just before 0xAC, and go back only one byte, that would
+				// leave us with a string that ends in the byte 0xE2, which is not a valid
+				// rune, so we need to try again.
+			} else {
+				break
+			}
+		}
+		text += clippingMessage
+	}
+	return text
+}
+
+func ClipOrSplitMessage(text string, length int, clippingMessage string, splitMax int) []string {
+	var msgParts []string
+	remainingText := text
+	// Invariant of this splitting loop: No text is lost (msgParts+remainingText is the original text),
+	// and all parts is guaranteed to satisfy the length requirement.
+	for len(msgParts) < splitMax-1 && len(remainingText) > length {
+		// Decision: The text needs to be split (again).
+		var chunk string
+		wasted := 0
+		// The longest UTF-8 encoding of a valid rune is 4 bytes (0xF4 0x8F 0xBF 0xBF, encoding U+10FFFF),
+		// so we should never need to waste 4 or more bytes at a time.
+		for wasted < 4 && wasted < length {
+			chunk = remainingText[:length-wasted]
+			if r, _ := utf8.DecodeLastRuneInString(chunk); r == utf8.RuneError {
+				wasted += 1
+			} else {
+				break
+			}
+		}
+		// Note: At this point, "chunk" might still be invalid, if "text" is very broken.
+		msgParts = append(msgParts, chunk)
+		remainingText = remainingText[len(chunk):]
+	}
+	msgParts = append(msgParts, ClipMessage(remainingText, length, clippingMessage))
+	return msgParts
+}
+
+// ParseMarkdown takes in an input string as markdown and parses it to html
+func ParseMarkdown(input string) string {
+	extensions := parser.HardLineBreak | parser.NoIntraEmphasis | parser.FencedCode
+	markdownParser := parser.NewWithExtensions(extensions)
+	renderer := html.NewRenderer(html.RendererOptions{
+		Flags: 0,
+	})
+	parsedMarkdown := markdown.ToHTML([]byte(input), markdownParser, renderer)
+	res := string(parsedMarkdown)
+	res = strings.TrimPrefix(res, "<p>")
+	res = strings.TrimSuffix(res, "</p>\n")
+	return res
+}
+
+// ConvertWebPToPNG converts input data (which should be WebP format) to PNG format
+func ConvertWebPToPNG(data *[]byte) error {
+	r := bytes.NewReader(*data)
+	m, err := webp.Decode(r)
+	if err != nil {
+		return err
+	}
+	var output []byte
+	w := bytes.NewBuffer(output)
+	if err := png.Encode(w, m); err != nil {
+		return err
+	}
+	*data = w.Bytes()
+	return nil
+}