Init

ext/instagram/util.go

@@ -0,0 +1,139 @@
+package instagram
+
+import (
+	"crypto/sha256"
+	"encoding/json"
+	"fmt"
+	"govd/util"
+	"html"
+	"io"
+	"net/http"
+	"net/url"
+	"regexp"
+	"strings"
+	"time"
+)
+
+var captionPattern = regexp.MustCompile(
+	`(?s)<meta property="og:title" content=".*?: &quot;(.*?)&quot;"`,
+)
+
+func BuildSignedPayload(contentURL string) (io.Reader, error) {
+	timestamp := fmt.Sprintf("%d", time.Now().UnixMilli())
+	hash := sha256.New()
+	_, err := io.WriteString(
+		hash,
+		contentURL+timestamp+apiKey,
+	)
+	if err != nil {
+		return nil, fmt.Errorf("error writing to SHA256 hash: %w", err)
+	}
+	secretBytes := hash.Sum(nil)
+	secretString := fmt.Sprintf("%x", secretBytes)
+	secretString = strings.ToLower(secretString)
+	payload := map[string]string{
+		"url":  contentURL,
+		"ts":   timestamp,
+		"_ts":  apiTimestamp,
+		"_tsc": "0", // ?
+		"_s":   secretString,
+	}
+	parsedPayload, err := json.Marshal(payload)
+	if err != nil {
+		return nil, fmt.Errorf("error marshalling payload: %w", err)
+	}
+	reader := strings.NewReader(string(parsedPayload))
+	return reader, nil
+}
+
+func ParseIGramResponse(body []byte) (*IGramResponse, error) {
+	var rawResponse interface{}
+	if err := json.Unmarshal(body, &rawResponse); err != nil {
+		return nil, fmt.Errorf("failed to decode response: %w", err)
+	}
+	switch rawResponse.(type) {
+	case []interface{}:
+		// array of IGramMedia
+		var media []*IGramMedia
+		if err := json.Unmarshal(body, &media); err != nil {
+			return nil, fmt.Errorf("failed to decode response: %w", err)
+		}
+		return &IGramResponse{
+			Items: media,
+		}, nil
+	case map[string]interface{}:
+		// single IGramMedia
+		var media IGramMedia
+		if err := json.Unmarshal(body, &media); err != nil {
+			return nil, fmt.Errorf("failed to decode response: %w", err)
+		}
+		return &IGramResponse{
+			Items: []*IGramMedia{&media},
+		}, nil
+	default:
+		return nil, fmt.Errorf("unexpected response type: %T", rawResponse)
+	}
+}
+
+func GetCDNURL(contentURL string) (string, error) {
+	parsedUrl, err := url.Parse(contentURL)
+	if err != nil {
+		return "", fmt.Errorf("can't parse igram URL: %v", err)
+	}
+	queryParams, err := url.ParseQuery(parsedUrl.RawQuery)
+	if err != nil {
+		return "", fmt.Errorf("can't unescape igram URL: %v", err)
+	}
+	cdnURL := queryParams.Get("uri")
+	return cdnURL, nil
+}
+
+func GetPostCaption(
+	postURL string,
+) (string, error) {
+	req, err := http.NewRequest(
+		http.MethodGet,
+		postURL,
+		nil,
+	)
+	if err != nil {
+		return "", fmt.Errorf("failed to create request: %w", err)
+	}
+	req.Header.Set("User-Agent", util.ChromeUA)
+	req.Header.Set("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8")
+	req.Header.Set("Accept-Language", "it-IT,it;q=0.8,en-US;q=0.5,en;q=0.3")
+	req.Header.Set("Referer", "https://www.instagram.com/accounts/onetap/?next=%2F")
+	req.Header.Set("Alt-Used", "www.instagram.com")
+	req.Header.Set("Connection", "keep-alive")
+	req.Header.Set("Cookie", `csrftoken=Ib2Zuvf1y9HkDwXFxkdang; sessionid=8569455296%3AIFQiov2eYfTdSd%3A19%3AAYfVHnaxecWGWhyzxvz60vu5qLn05DyKgN_tTZUXTA; ds_user_id=8569455296; mid=Z_j1vQAEAAGVUE3KuxMR7vBonGBw; ig_did=BC48C8B7-D71B-49EF-8195-F9DE37A57B49; rur="CLN\0548569455296\0541775905137:01f7ebda5b896815e9279bb86a572db6bdc8ebccf3e1f8d5327e2bc5ca187fd5cd932b66"; wd=513x594; datr=x_X4Z_CHqpwtjaRKq7PtCNu3`)
+	req.Header.Set("Upgrade-Insecure-Requests", "1")
+	req.Header.Set("Sec-Fetch-Dest", "document")
+	req.Header.Set("Sec-Fetch-Mode", "navigate")
+	req.Header.Set("Sec-Fetch-Site", "same-origin")
+	req.Header.Set("Priority", "u=0, i")
+	req.Header.Set("Pragma", "no-cache")
+	req.Header.Set("Cache-Control", "no-cache")
+	req.Header.Set("TE", "trailers")
+
+	resp, err := HTTPClient.Do(req)
+	if err != nil {
+		return "", fmt.Errorf("failed to send request: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return "", fmt.Errorf("failed to get response: %s", resp.Status)
+	}
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return "", fmt.Errorf("failed to read response body: %w", err)
+	}
+
+	matches := captionPattern.FindStringSubmatch(string(body))
+	if len(matches) < 2 {
+		// post has no caption most likely
+		return "", nil
+	} else {
+		return html.UnescapeString(matches[1]), nil
+	}
+}