feat: parse url with js plugins support (#96)

* feat: WIP. add parser functionality and text message handling

* fix: use json to marshal js result

* feat: add metadata handling and version validation for jsParser

* refactor: rename parser package to parsers and restructure parser handling

* refactor: core code struct and impl parse task handle

* feat: impl parsed download

* fix: seek cache file when processing tph picture

* feat: implement parsed task handling and progress tracking

* feat: enhance task processing with concurrency control and progress tracking

* feat: add resource ID generation and improve resource processing handling

* feat: improve message formatting in parsed text and progress completion

* feat: add example js plugin

* feat: implement Twitter parser

* fix: twitter parse video json decode error

* feat: impl stream mode for parse task

pkg/parser/parser.go

@@ -0,0 +1,63 @@
+package parser
+
+import (
+	"crypto/md5"
+	"fmt"
+)
+
+type Parser interface {
+	CanHandle(url string) bool
+	Parse(url string) (*Item, error)
+}
+
+// Resource is a single downloadable resource with metadata.
+type Resource struct {
+	URL       string            `json:"url"`
+	Filename  string            `json:"filename"` // with ext
+	MimeType  string            `json:"mime_type"`
+	Extension string            `json:"extension"`
+	Size      int64             `json:"size"`    // 0 when unknown
+	Hash      map[string]string `json:"hash"`    // {"md5": "...", "sha256": "..."}
+	Headers   map[string]string `json:"headers"` // HTTP headers when downloading
+	Extra     map[string]any    `json:"extra"`
+}
+
+type Item struct {
+	Site        string         `json:"site"`
+	URL         string         `json:"url"` // original URL of the item
+	Title       string         `json:"title"`
+	Author      string         `json:"author"`
+	Description string         `json:"description"`
+	Tags        []string       `json:"tags"`
+	Resources   []Resource     `json:"resources"`
+	Extra       map[string]any `json:"extra"`
+}
+
+func (r *Resource) FileName() string {
+	return r.Filename
+}
+
+func (r *Resource) FileSize() int64 {
+	return r.Size
+}
+
+func (r *Resource) ID() string {
+	h := md5.New()
+	h.Write([]byte(r.URL))
+	h.Write([]byte(r.Filename))
+	h.Write([]byte(r.MimeType))
+	h.Write([]byte(r.Extension))
+	h.Write([]byte(fmt.Sprintf("%d", r.Size)))
+
+	for k, v := range r.Hash {
+		h.Write([]byte(k))
+		h.Write([]byte(v))
+	}
+
+	for k, v := range r.Headers {
+		h.Write([]byte(k))
+		h.Write([]byte(v))
+	}
+
+	return fmt.Sprintf("%x", h.Sum(nil))
+}