func ParseHtml(io io.Reader, ps []post.Post) (psout []post.Post, err error) {
// Create a qoquery document to parse from
doc, err := goquery.NewDocumentFromReader(io)
checkErr(err, "Failed to parse HTML")
if err == nil {
fmt.Println("---- Starting to parse ------------------------")
// Find reddit posts = elements with class "thing"
thing := doc.Find(".thing")
for iThing := range thing.Nodes {
post := post.NewPost()
// use `single` as a selection of 1 node
singlething := thing.Eq(iThing)
// get the reddit post identifier
reddit_post_id, exists := singlething.Attr("data-fullname")
if exists == false {
singlehtml, _ := singlething.Html()
post.Err = fmt.Errorf("data-fullname not found in %s", singlehtml)
} else {
// find an element with class title and a child with class may-blank
// Remove CRLF and unnecessary whitespaces
post.Title = stringMinifier(singlething.Find(".title .may-blank").Text())
post.PostId = reddit_post_id
post.User = singlething.Find(".author").Text()
post.Url, _ = singlething.Find(".comments.may-blank").Attr("href")
post.SetScore(singlething.Find(".score.likes").Text())
reddit_postdate, exists := singlething.Find("time").Attr("datetime")
if exists == false {
singlehtml, _ := singlething.Html()
post.Err = fmt.Errorf("datetime not found in %s", singlehtml)
} else {
//post := post.NewPost()
post.SetPostDate(reddit_postdate)
// Print out the crawled info
post.String()
fmt.Println("-----------------------------------------------")
}
}
ps = append(ps, post)
}
}
return ps, err
}
// Parse for posts in html from hackernews, input html is an io.Reader and returns recognized posts in a psout slice of posts.
// Errors which affect only a single post are stored in their post.Err
func ParseHtmlHackerNews(body io.Reader, ps []*post.Post) (psout []*post.Post, err error) {
var html string
// Create a qoquery document to parse from an io.Reader
doc, err := goquery.NewDocumentFromReader(body)
if err != nil {
return ps, errors.New("Failed to parse HTML: " + err.Error())
}
// Find hackernews posts = elements with class "athing"
thing := doc.Find(".athing")
for iThing := range thing.Nodes {
// Create a new post struct - if the crawling fails the post will have an Err attached
// but will be added to the outgoing (psout) slice nevertheless
post := post.NewPost()
post.Site = "hackernews"
ps = append(ps, &post)
// use `singlearticle` as a selection of one single post
singlearticle := thing.Eq(iThing)
// Get the next element containing additional info for this post
scorenode := singlearticle.Next()
if scorenode == nil {
errhtml, _ := singlearticle.Html()
post.Err = fmt.Errorf("Did not find next sibling for: %s\n", errhtml)
continue
}
htmlpost := singlearticle.Find(".title a").First()
if htmlpost.Size() == 0 {
errhtml, _ := singlearticle.Html()
post.Err = fmt.Errorf("Did not find title for: %s\n", errhtml)
continue
}
post.Title = htmlpost.Text()
var exists bool
post.Url, exists = htmlpost.Attr("href")
if exists == false {
singlehtml, _ := htmlpost.Html()
post.Err = fmt.Errorf("href not found in %s\n", singlehtml)
}
post.Url = stringMinifier(post.Url)
if !(strings.HasPrefix(post.Url, "http")) {
post.Url = "https://news.ycombinator.com/" + post.Url
}
if DebugLevel > 2 {
fmt.Printf("**** URL post.Url: %s\n", post.Url)
}
if DebugLevel > 3 {
fmt.Printf("---------------------------\n")
html, _ = scorenode.Html()
fmt.Printf("HTML: %s\n", html)
fmt.Printf("---------------------------\n")
}
// Get the score
scoretag := scorenode.Find(".subtext .score").First()
if scoretag.Size() == 0 {
post.Err = fmt.Errorf("Did not find score for: %v\n", scorenode)
continue
}
if DebugLevel > 3 {
fmt.Printf("------- SCORE -------------\n")
html, _ = scoretag.Html()
fmt.Printf("HTML: %s\n", html)
score := scoretag.Text()
fmt.Printf("TEXT: %s\n", score)
fmt.Printf("---------------------------\n")
}
post.SetScore(strings.Split(scoretag.Text(), " ")[0])
postid, exists := scoretag.Attr("id")
if !exists {
html, _ = scoretag.Html()
post.Err = fmt.Errorf("Did not find postid in %s\n", html)
}
if DebugLevel > 3 {
fmt.Printf("------- POST ID -----------\n")
fmt.Printf("TEXT: %s\n", postid)
fmt.Printf("---------------------------\n")
}
post.WebPostId = strings.Split(postid, "_")[1]
// Get the username and postdate
hrefs := scorenode.Find(".subtext a")
if hrefs.Size() == 0 {
errhtml, _ := scorenode.Html()
post.Err = fmt.Errorf("Did not find user and date in %s\n", errhtml)
continue
}
for i := range hrefs.Nodes {
href := hrefs.Eq(i)
t, _ := href.Html()
s, exists := href.Attr("href")
if exists {
if strings.HasPrefix(s, "user?id") {
post.User = t
continue
}
if strings.HasPrefix(s, "item?id") {
if strings.Contains(t, "ago") {
var postDate time.Time
postDate, err = GetDateFromCreatedAgo(t)
if err != nil {
post.Err = errors.New(fmt.Sprintf("Failed to convert to date: %s: %s\n", t, err.Error()))
continue
}
post.PostDate = postDate
post.Err = err
}
}
}
if DebugLevel > 3 {
fmt.Printf("------- HREF --------------\n")
fmt.Printf("TEXT: %s\n", t)
fmt.Printf("HREF: %s\n", s)
fmt.Printf("---------------------------\n")
}
}
if post.Err == nil {
err = ParseHtmlComments(&post)
}
if DebugLevel > 2 && err == nil {
fmt.Printf("------ POST DUMP -----------\n")
fmt.Print(post.String("PARSED: "))
fmt.Printf("------ POST DUMP END -------\n")
}
}
return ps, err
}
func RedditPostScraper(sub string) (err error) {
// connect to db using standard Go database/sql API
//db, err := sql.Open("mysql", "user:password@/dbname")
db, err := sql.Open("mysql", "golang:golang@/golang")
if err != nil {
return errors.New("sql.Open failed: " + err.Error())
}
// Open doesn't open a connection. Validate DSN data:
err = db.Ping()
if err != nil {
return errors.New("db.Ping failed: " + err.Error())
}
// construct a gorp DbMap
dbmap := &gorp.DbMap{Db: db, Dialect: gorp.MySQLDialect{"InnoDB", "UTF8"}}
defer dbmap.Db.Close()
// register the structs you wish to use with gorp
// you can also use the shorter dbmap.AddTable() if you
// don't want to override the table name
//
// SetKeys(true) means we have a auto increment primary key, which
// will get automatically bound to your struct post-insert
table := dbmap.AddTableWithName(post.Post{}, "posts")
table.SetKeys(true, "Id")
// Set field Site to be a varchar(32)
table.ColMap("Site").SetMaxSize(32)
// Set field Site to be not null
table.ColMap("Site").SetNotNull(true)
// Set field PostId to be a varchar(32)
table.ColMap("PostId").SetMaxSize(32)
// Set field PostId to be not null
table.ColMap("PostId").SetNotNull(true)
// this creates an unique index on PostId
table.ColMap("PostId").SetUnique(true)
// create the table. in a production system you'd generally
// use a migration tool, or create the tables via scripts
err = dbmap.CreateTablesIfNotExists()
if err != nil {
return errors.New("Create table 'posts' failed: " + err.Error())
}
// Get data from reddit
geturl := "http://www.reddit.com/r/" + sub + "/new"
resp, err := http.Get(geturl)
if err != nil {
return errors.New("Failed to http.Get from " + geturl + ": " + err.Error())
}
if resp != nil {
if resp.Body == nil {
return errors.New("Body from " + geturl + " is nil!")
} else {
defer resp.Body.Close()
}
} else {
return errors.New("Response from " + geturl + " is nil!")
}
if resp.StatusCode != 200 { // 200 = OK
httperr := fmt.Sprintf("Failed to http.Get from %s: Http Status code: %d: Msg: %s", geturl, resp.StatusCode, resp.Status)
return errors.New(httperr)
}
// Create a new post slice and then parse the response body into ps
ps := make([]post.Post, 0)
ps, err = ParseHtmlReddit(resp.Body, ps)
if err != nil {
return errors.New("Error in RedditParseHtml: " + geturl + ": " + err.Error())
}
foundnewposts := false
// insert rows - auto increment PKs will be set properly after the insert
for _, post := range ps {
if post.Err == nil {
// check if post already exists
count, err := dbmap.SelectInt("select count(*) from posts where PostId = ?", post.PostId)
if err != nil {
return errors.New("select count(*) from posts failed: " + err.Error())
}
if count == 0 {
foundnewposts = true
err = dbmap.Insert(&post)
if err != nil {
return errors.New("insert into table posts failed: " + err.Error())
}
if err == nil {
// Print out the crawled info
fmt.Println(post.String())
fmt.Println("-----------------------------------------------")
}
}
} else {
fmt.Println("Single post error in " + geturl + ": " + post.Err.Error())
}
}
if !foundnewposts {
fmt.Println("No new posts found at " + geturl)
}
return
}