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Add method to request all posts, optimize query to only execute one db query

This commit is contained in:
Jan-Lukas Else 2020-08-05 18:41:45 +02:00
parent 31591d694c
commit fa10bd03d3
1 changed files with 36 additions and 19 deletions
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55
posts.go
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@ -32,34 +32,51 @@ func servePost(w http.ResponseWriter, r *http.Request) {
}
func getPost(context context.Context, path string) (*Post, error) {
queriedPost := &Post{}
row := appDb.QueryRowContext(context, "select path, COALESCE(content, ''), COALESCE(published, ''), COALESCE(updated, '') from posts where path=?", path)
err := row.Scan(&queriedPost.Path, &queriedPost.Content, &queriedPost.Published, &queriedPost.Updated)
if err == sql.ErrNoRows {
return nil, errPostNotFound
} else if err != nil {
return nil, err
}
err = queriedPost.fetchParameters(context)
posts, err := getPosts(context, path)
if err != nil {
return nil, err
} else if len(posts) == 0 {
return nil, errPostNotFound
}
return queriedPost, nil
return posts[0], nil
}
func (p *Post) fetchParameters(context context.Context) error {
rows, err := appDb.QueryContext(context, "select parameter, COALESCE(value, '') from post_parameters where path=?", p.Path)
func getAllPosts(context context.Context) (posts []*Post, err error) {
return getPosts(context, "")
}
func getPosts(context context.Context, path string) (posts []*Post, err error) {
paths := make(map[string]int)
var rows *sql.Rows
if path != "" {
rows, err = appDb.QueryContext(context, "select p.path, COALESCE(content, ''), COALESCE(published, ''), COALESCE(updated, ''), COALESCE(parameter, ''), COALESCE(value, '') from posts p left outer join post_parameters pp on p.path = pp.path where p.path=?", path)
} else {
rows, err = appDb.QueryContext(context, "select p.path, COALESCE(content, ''), COALESCE(published, ''), COALESCE(updated, ''), COALESCE(parameter, ''), COALESCE(value, '') from posts p left outer join post_parameters pp on p.path = pp.path")
}
if err != nil {
return err
return nil, err
}
p.Parameters = make(map[string]string)
defer func() {
_ = rows.Close()
}()
for rows.Next() {
var parameter string
var value string
_ = rows.Scan(&parameter, &value)
p.Parameters[parameter] = value
post := &Post{}
var parameterName, parameterValue string
err = rows.Scan(&post.Path, &post.Content, &post.Published, &post.Updated, &parameterName, &parameterValue)
if err != nil {
return nil, err
}
if paths[post.Path] == 0 {
index := len(posts)
paths[post.Path] = index + 1
post.Parameters = make(map[string]string)
posts = append(posts, post)
}
if parameterName != "" && posts != nil {
posts[paths[post.Path]-1].Parameters[parameterName] = parameterValue
}
}
return nil
return posts, nil
}
func allPostPaths() ([]string, error) {