Add reddit source (#22)

source/reddit.go

@@ -0,0 +1,70 @@
+package source
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+
+	"github.com/ioki-mobility/summaraizer"
+)
+
+// Reddit is a source that fetches comments from a Reddit post.
+type Reddit struct {
+	UrlPath string // The path to the Reddit post. Everything after `https://www.reddit.com`.
+}
+
+// Fetch fetches comments from a Reddit post.
+func (r *Reddit) Fetch() (summaraizer.Comments, error) {
+	request, err := http.NewRequest("GET", "https://www.reddit.com"+r.UrlPath+".json", nil)
+	request.Header.Set("User-Agent", "Go:summaraizer:0.0.0")
+	if err != nil {
+		return nil, err
+	}
+	resp, err := http.DefaultClient.Do(request)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, err
+	}
+
+	var response []redditResponse
+	err = json.Unmarshal(body, &response)
+	if err != nil {
+		return nil, err
+	}
+
+	var comments summaraizer.Comments
+	firstPost := response[0].Data.Children[0].Data
+	fistPostBody := fmt.Sprintf("%s\n\n%s", firstPost.Title, firstPost.Selftext)
+	comments = append(comments, summaraizer.Comment{
+		Author: firstPost.Author,
+		Body:   fistPostBody,
+	})
+	if len(response) == 2 {
+		for _, child := range response[1].Data.Children {
+			comments = append(comments, summaraizer.Comment{
+				Author: child.Data.Author,
+				Body:   child.Data.Body,
+			})
+		}
+	}
+	return comments, nil
+}
+
+type redditResponse struct {
+	Data struct {
+		Children []struct {
+			Data struct {
+				Author   string `json:"author"`
+				Title    string `json:"title,omitempty"`
+				Selftext string `json:"selftext,omitempty"`
+				Body     string `json:"body,omitempty"`
+			} `json:"data"`
+		} `json:"children"`
+	} `json:"data"`
+}