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|
package main
// Mirroring Stud.IP into the database.
//
// Two kinds of run:
//
// - a poll, every few minutes: the activity stream since the last poll, the
// message boxes, and a content sync of every course the stream mentions.
// It doubles as the keepalive of the session.
// - a full run, hourly: semesters, the course list, and a content sync of
// every course still in it. This catches whatever the activity stream does
// not report, which is more than nothing — it is a feed for people, not a
// change log.
//
// Nothing here deletes. Something missing from a complete listing gets
// gone_at; something that reappears loses it again. A listing that failed is
// not complete, and marks nothing.
import (
"context"
"crypto/sha256"
"database/sql"
"encoding/hex"
"encoding/json"
"errors"
"fmt"
"log"
"net/http"
"net/url"
"strconv"
"strings"
"sync"
"time"
)
type syncer struct {
db *database
c *studip
maxFile int64
now func() time.Time
run sync.Mutex // one run at a time
trigger chan struct{}
mu sync.Mutex
running string // "", "poll", "full"
runningAt time.Time
}
func newSyncer(db *database, c *studip, maxFile int64) *syncer {
return &syncer{db: db, c: c, maxFile: maxFile, now: time.Now, trigger: make(chan struct{}, 1)}
}
// kick asks for a full run as soon as possible. Never blocks; a kick while
// one is pending is the same kick.
func (s *syncer) kick() {
select {
case s.trigger <- struct{}{}:
default:
}
}
func (s *syncer) state() (string, time.Time) {
s.mu.Lock()
defer s.mu.Unlock()
return s.running, s.runningAt
}
// loop runs forever: a full run at start and on every kick and every full
// interval, a poll every poll interval in between. Without a live session it
// only waits for a kick, which /login sends.
func (s *syncer) loop(ctx context.Context, poll, full time.Duration) {
lastFull := time.Time{}
timer := time.NewTimer(0)
for {
kicked := false
select {
case <-ctx.Done():
return
case <-timer.C:
case <-s.trigger:
kicked = true
}
if s.c.current() == nil {
timer.Reset(poll)
continue
}
if kicked || s.now().Sub(lastFull) >= full {
if err := s.runOnce(ctx, "full"); err == nil || !errors.Is(err, errSessionDied) {
lastFull = s.now()
}
} else {
s.runOnce(ctx, "poll")
}
if !timer.Stop() {
select {
case <-timer.C:
default:
}
}
timer.Reset(poll)
}
}
func (s *syncer) runOnce(ctx context.Context, kind string) error {
s.run.Lock()
defer s.run.Unlock()
s.mu.Lock()
s.running, s.runningAt = kind, s.now()
s.mu.Unlock()
defer func() {
s.mu.Lock()
s.running = ""
s.mu.Unlock()
}()
s.c.mu.Lock()
s.c.requests = 0
s.c.mu.Unlock()
start := s.now()
res, _ := s.db.Write.Exec(`INSERT INTO sync_runs (kind, started_at) VALUES (?, ?)`, kind, start.Unix())
runID, _ := res.LastInsertId()
r := &run{s: s, seq: runID}
var err error
if kind == "full" {
err = r.full(ctx)
} else {
err = r.poll(ctx)
}
s.c.mu.Lock()
reqs := s.c.requests
s.c.mu.Unlock()
var msg sql.NullString
if err != nil {
msg = sql.NullString{String: err.Error(), Valid: true}
log.Printf("sync %s: %v", kind, err)
}
s.db.Write.Exec(`UPDATE sync_runs SET finished_at = ?, requests = ?, downloaded = ?, error = ? WHERE id = ?`,
s.now().Unix(), reqs, r.downloaded, msg, runID)
// Keep the run log bounded; it is for /status, not an archive.
s.db.Write.Exec(`DELETE FROM sync_runs WHERE id < ? - 2000`, runID)
log.Printf("sync %s: %d requests, %d files downloaded, %s", kind, reqs, r.downloaded, s.now().Sub(start).Round(time.Second))
return err
}
// run is the state of one sync run.
type run struct {
s *syncer
downloaded int
// seq is this run's id in sync_runs. Rows record the run that last saw
// them in last_seen, and a sweep marks gone what a complete listing in
// this run did not contain (last_seen < seq). A timestamp would not do:
// two runs within one second would each think the other's rows current.
seq int64
}
func (r *run) db() *sql.DB { return r.s.db.Write }
func (r *run) now() int64 { return r.s.now().Unix() }
// fatal reports errors that make going on pointless: no session, or the
// context ending. Anything else is one course's or one item's problem.
func fatal(err error) bool {
return errors.Is(err, errNoSession) || errors.Is(err, errSessionDied) ||
errors.Is(err, context.Canceled) || errors.Is(err, context.DeadlineExceeded)
}
// unavailable is a listing a course does not offer: the tool (forum, news,
// files) is switched off there, or closed to this account.
func unavailable(err error) bool {
var he *httpError
return errors.As(err, &he) && (he.Status == http.StatusForbidden || he.Status == http.StatusNotFound)
}
func (r *run) full(ctx context.Context) error {
sess := r.s.c.current()
if sess == nil {
return errNoSession
}
if err := r.semesters(ctx); err != nil {
return err
}
courses, err := r.courses(ctx, sess.UserID)
if err != nil {
return err
}
siteOK := true
if err := r.messages(ctx, sess.UserID); err != nil {
if fatal(err) {
return err
}
siteOK = false
log.Printf("messages: %v", err)
}
if err := r.news(ctx, "studip", "/studip/news"); err != nil {
if fatal(err) {
return err
}
siteOK = false
log.Printf("site news: %v", err)
}
// The account's first complete look at its messages and site news is
// over; from now on what appears there is news. See quiet.
if siteOK && getState(r.db(), "baselined") == "" {
setState(r.db(), "baselined", strconv.FormatInt(r.now(), 10))
}
// The activity cursor moves on a full run too, so the next poll does not
// redo what this run has just covered.
if _, err := r.activities(ctx, sess.UserID); err != nil {
if fatal(err) {
return err
}
log.Printf("activity stream: %v", err)
}
var errs []string
for _, id := range courses {
if err := r.course(ctx, id); err != nil {
if fatal(err) {
return err
}
errs = append(errs, err.Error())
}
}
if len(errs) > 0 {
return fmt.Errorf("%d course(s) failed: %s", len(errs), strings.Join(errs, "; "))
}
return nil
}
func (r *run) poll(ctx context.Context) error {
sess := r.s.c.current()
if sess == nil {
return errNoSession
}
touched, err := r.activities(ctx, sess.UserID)
if err != nil {
return err
}
if err := r.messages(ctx, sess.UserID); err != nil {
if fatal(err) {
return err
}
log.Printf("messages: %v", err)
}
for _, id := range touched {
var gone sql.NullInt64
if r.db().QueryRow(`SELECT gone_at FROM courses WHERE id = ?`, id).Scan(&gone) != nil || gone.Valid {
// A course the mirror does not know (or no longer follows) is
// the next full run's business: it knows the semester, the title,
// and whether the account is still in it.
continue
}
if err := r.course(ctx, id); err != nil && fatal(err) {
return err
}
}
return nil
}
// ============================================================================
// Change log
// ============================================================================
func (r *run) record(kind, id, course, event, title string, date int64) {
r.recordSeen(kind, id, course, event, title, date, r.quiet(course))
}
// recordSeen records a change that is seen already when seen is set: what a
// first sync finds, or what the reader did themselves.
func (r *run) recordSeen(kind, id, course, event, title string, date int64, seen bool) {
if date == 0 {
date = r.now()
}
var c sql.NullString
if course != "" {
c = sql.NullString{String: course, Valid: true}
}
var seenAt sql.NullInt64
if seen {
seenAt = sql.NullInt64{Int64: r.now(), Valid: true}
}
r.db().Exec(`INSERT INTO changes (observed_at, date, kind, item_id, course_id, event, title, seen_at)
VALUES (?, ?, ?, ?, ?, ?, ?, ?)`, r.now(), date, kind, id, c, event, title, seenAt)
}
// quiet says whether what is found now is the first sync of its scope — a
// course, or with course "" the account's messages and site news — and so
// is the backlog rather than news. It is recorded, but as seen: the first
// page of a new mirror, or after joining a course, would otherwise be a
// semester's worth of "new". See SEEN in campusweb(1).
func (r *run) quiet(course string) bool {
if course == "" {
return getState(r.db(), "baselined") == ""
}
var at sql.NullInt64
r.db().QueryRow(`SELECT baselined_at FROM courses WHERE id = ?`, course).Scan(&at)
return !at.Valid
}
// sweep marks rows of a table gone that a complete listing no longer
// contained, and records each. scope is the WHERE clause naming what the
// listing covered.
func (r *run) sweep(table, kind, titleCol, courseCol, scope string, since int64, args ...any) {
q := fmt.Sprintf(`SELECT id, %s, %s FROM %s WHERE gone_at IS NULL AND last_seen < ? AND %s`,
titleCol, courseCol, table, scope)
rows, err := r.db().Query(q, append([]any{since}, args...)...)
if err != nil {
log.Printf("sweep %s: %v", table, err)
return
}
type gone struct{ id, title, course string }
var gs []gone
for rows.Next() {
var g gone
var t, c sql.NullString
rows.Scan(&g.id, &t, &c)
g.title, g.course = t.String, c.String
gs = append(gs, g)
}
rows.Close()
for _, g := range gs {
r.db().Exec(fmt.Sprintf(`UPDATE %s SET gone_at = ? WHERE id = ?`, table), r.now(), g.id)
r.record(kind, g.id, g.course, "gone", g.title, 0)
}
}
// ============================================================================
// Semesters and courses
// ============================================================================
func (r *run) semesters(ctx context.Context) error {
items, _, err := r.s.c.list(ctx, "/semesters", nil)
if err != nil {
return fmt.Errorf("semesters: %w", err)
}
for _, it := range items {
var a struct {
Title string `json:"title"`
Start string `json:"start"`
End string `json:"end"`
LectStart string `json:"start-of-lectures"`
LectEnd string `json:"end-of-lectures"`
IsCurrent bool `json:"is-current"`
}
if err := it.attrs(&a); err != nil {
return err
}
if _, err := r.db().Exec(`INSERT INTO semesters (id, title, start, end, lect_start, lect_end, is_current)
VALUES (?, ?, ?, ?, ?, ?, ?)
ON CONFLICT (id) DO UPDATE SET title = excluded.title, start = excluded.start, end = excluded.end,
lect_start = excluded.lect_start, lect_end = excluded.lect_end, is_current = excluded.is_current`,
it.ID, a.Title, parseTime(a.Start), parseTime(a.End), parseTime(a.LectStart), parseTime(a.LectEnd), a.IsCurrent); err != nil {
return err
}
}
return nil
}
// courses refreshes the course list and returns the ids to sync.
func (r *run) courses(ctx context.Context, userID string) ([]string, error) {
t0 := r.seq
items, _, err := r.s.c.list(ctx, "/users/"+url.PathEscape(userID)+"/courses", nil)
if err != nil {
return nil, fmt.Errorf("course list: %w", err)
}
var ids []string
for _, it := range items {
var a struct {
Number *string `json:"course-number"`
Title string `json:"title"`
Subtitle *string `json:"subtitle"`
Description *string `json:"description"`
Location *string `json:"location"`
Misc *string `json:"miscellaneous"`
Audience *string `json:"audience"`
Require *string `json:"requirements"`
Teaching *string `json:"teaching-method"`
Achievement *string `json:"achievement"`
Credits *string `json:"credits"`
}
if err := it.attrs(&a); err != nil {
return nil, err
}
var start, end sql.NullString
if v := it.rel("start-semester"); v != "" {
start = sql.NullString{String: v, Valid: true}
}
if v := it.rel("end-semester"); v != "" {
end = sql.NullString{String: v, Valid: true}
}
if _, err := r.db().Exec(`INSERT INTO courses (id, title, subtitle, number, description, location,
miscellaneous, audience, requirements, teaching_method, achievement, credits,
start_semester, end_semester, first_seen, last_seen)
VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
ON CONFLICT (id) DO UPDATE SET title = excluded.title, subtitle = excluded.subtitle,
number = excluded.number, description = excluded.description, location = excluded.location,
miscellaneous = excluded.miscellaneous, audience = excluded.audience,
requirements = excluded.requirements, teaching_method = excluded.teaching_method,
achievement = excluded.achievement, credits = excluded.credits,
start_semester = excluded.start_semester, end_semester = excluded.end_semester,
last_seen = excluded.last_seen, gone_at = NULL`,
it.ID, a.Title, a.Subtitle, a.Number, a.Description, a.Location,
a.Misc, a.Audience, a.Require, a.Teaching, a.Achievement, a.Credits,
start, end, r.now(), r.seq); err != nil {
return nil, err
}
ids = append(ids, it.ID)
}
// A course left is kept with everything in it; it is only no longer synced.
r.db().Exec(`UPDATE courses SET gone_at = ? WHERE gone_at IS NULL AND last_seen < ?`, r.now(), t0)
return ids, nil
}
// course syncs everything inside one course. Each part fails on its own, so
// a forum that errors does not cost the files.
func (r *run) course(ctx context.Context, id string) error {
var title string
r.db().QueryRow(`SELECT title FROM courses WHERE id = ?`, id).Scan(&title)
parts := []struct {
name string
f func(context.Context, string) error
}{
{"files", r.files},
{"news", func(ctx context.Context, id string) error {
return r.news(ctx, id, "/courses/"+url.PathEscape(id)+"/news")
}},
{"dates", r.events},
{"forum", r.forum},
{"wiki", r.wiki},
{"information pages", r.info},
}
var errs []string
for _, p := range parts {
if err := p.f(ctx, id); err != nil {
if fatal(err) {
return err
}
errs = append(errs, p.name+": "+err.Error())
}
}
// The first sync of the course is over, even if a part of it failed:
// a part that keeps failing must not keep everything else quiet.
r.db().Exec(`UPDATE courses SET baselined_at = ? WHERE id = ? AND baselined_at IS NULL`, r.now(), id)
if len(errs) > 0 {
msg := strings.Join(errs, "; ")
r.db().Exec(`UPDATE courses SET sync_error = ? WHERE id = ?`, msg, id)
return fmt.Errorf("%s: %s", title, msg)
}
r.db().Exec(`UPDATE courses SET synced_at = ?, sync_error = NULL WHERE id = ?`, r.now(), id)
return nil
}
// ============================================================================
// Files
// ============================================================================
func (r *run) files(ctx context.Context, course string) error {
t0 := r.seq
cpath := "/courses/" + url.PathEscape(course)
folders, _, err := r.s.c.list(ctx, cpath+"/folders", nil)
if unavailable(err) {
return nil
}
if err != nil {
return err
}
for _, it := range folders {
var a struct {
Type string `json:"folder-type"`
Name string `json:"name"`
Description *string `json:"description"`
Mkdate string `json:"mkdate"`
Chdate string `json:"chdate"`
}
if err := it.attrs(&a); err != nil {
return err
}
var parent sql.NullString
if p := it.rel("parent"); p != "" {
parent = sql.NullString{String: p, Valid: true}
}
if _, err := r.db().Exec(`INSERT INTO folders (id, course_id, parent_id, name, description, folder_type,
mkdate, chdate, first_seen, last_seen)
VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
ON CONFLICT (id) DO UPDATE SET course_id = excluded.course_id, parent_id = excluded.parent_id,
name = excluded.name, description = excluded.description, folder_type = excluded.folder_type,
mkdate = excluded.mkdate, chdate = excluded.chdate, last_seen = excluded.last_seen, gone_at = NULL`,
it.ID, course, parent, a.Name, a.Description, a.Type, parseTime(a.Mkdate), parseTime(a.Chdate), r.now(), r.seq); err != nil {
return err
}
}
r.db().Exec(`UPDATE folders SET gone_at = ? WHERE gone_at IS NULL AND last_seen < ? AND course_id = ?`, r.now(), t0, course)
refs, _, err := r.s.c.list(ctx, cpath+"/file-refs", nil)
if err != nil {
return err
}
var errs []string
for _, it := range refs {
if err := r.file(ctx, course, it); err != nil {
if fatal(err) {
return err
}
errs = append(errs, err.Error())
}
}
r.sweep("files", "file", "name", "course_id", "course_id = ?", t0, course)
if len(errs) > 0 {
return fmt.Errorf("%d file(s) not downloaded: %s", len(errs), strings.Join(errs, "; "))
}
return nil
}
func (r *run) file(ctx context.Context, course string, it resource) error {
var a struct {
Name string `json:"name"`
Description string `json:"description"`
Mkdate string `json:"mkdate"`
Chdate string `json:"chdate"`
Size int64 `json:"filesize"`
Mime string `json:"mime-type"`
Downloadable bool `json:"is-downloadable"`
}
if err := it.attrs(&a); err != nil {
return err
}
// The owner's name comes along in the relationship's meta, which saves
// a request per uploader.
var owner struct {
Meta struct {
Name string `json:"name"`
} `json:"meta"`
}
json.Unmarshal(it.Relationships["owner"], &owner)
mk, ch := parseTime(a.Mkdate), parseTime(a.Chdate)
var oldCh, oldGone sql.NullInt64
var oldLink sql.NullString
err := r.db().QueryRow(`SELECT chdate, gone_at, link_url FROM files WHERE id = ?`, it.ID).Scan(&oldCh, &oldGone, &oldLink)
isNew := errors.Is(err, sql.ErrNoRows)
if err != nil && !isNew {
return err
}
if _, err := r.db().Exec(`INSERT INTO files (id, course_id, folder_id, name, description, mime, size, mkdate, chdate,
owner, downloadable, first_seen, last_seen)
VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
ON CONFLICT (id) DO UPDATE SET course_id = excluded.course_id, folder_id = excluded.folder_id,
name = excluded.name, description = excluded.description, mime = excluded.mime, size = excluded.size,
mkdate = excluded.mkdate, chdate = excluded.chdate, owner = excluded.owner,
downloadable = excluded.downloadable, last_seen = excluded.last_seen, gone_at = NULL`,
it.ID, course, it.rel("parent"), a.Name, a.Description, a.Mime, a.Size, mk, ch,
owner.Meta.Name, a.Downloadable, r.now(), r.seq); err != nil {
return err
}
switch {
case isNew:
r.record("file", it.ID, course, "new", a.Name, mk)
case oldCh.Int64 != ch:
r.record("file", it.ID, course, "changed", a.Name, ch)
case oldGone.Valid:
r.record("file", it.ID, course, "new", a.Name+" (back)", 0)
}
// Download when there is no version yet, or the newest one was fetched
// at another chdate. A file that failed before is retried every run.
var lastCh sql.NullInt64
var lastSum string
var n int
err = r.db().QueryRow(`SELECT n, chdate, sha256 FROM file_versions WHERE file_id = ? ORDER BY n DESC LIMIT 1`,
it.ID).Scan(&n, &lastCh, &lastSum)
if err != nil && !errors.Is(err, sql.ErrNoRows) {
return err
}
if n > 0 && lastCh.Int64 == ch {
return nil
}
if oldLink.Valid && oldCh.Int64 == ch {
// A link whose target is known and that has not changed.
return nil
}
if !a.Downloadable {
r.db().Exec(`UPDATE files SET fetch_error = 'Stud.IP does not let this account download it' WHERE id = ?`, it.ID)
return nil
}
if a.Size > r.s.maxFile {
r.db().Exec(`UPDATE files SET fetch_error = ? WHERE id = ?`,
fmt.Sprintf("%d bytes, more than --max-file-size", a.Size), it.ID)
return nil
}
data, err := r.s.c.content(ctx, it.ID, r.s.maxFile)
var he *httpError
if errors.As(err, &he) && he.Status == http.StatusInternalServerError {
// Most likely a link, which the JSON:API cannot serve; see
// linkTarget. Anything else keeps the original error.
var meta struct {
DownloadURL string `json:"download-url"`
}
json.Unmarshal(it.Meta, &meta)
if target, lerr := r.s.c.linkTarget(ctx, meta.DownloadURL); lerr == nil && target != "" {
_, err := r.db().Exec(`UPDATE files SET link_url = ?, fetch_error = NULL WHERE id = ?`, target, it.ID)
return err
} else if fatal(lerr) {
return lerr
}
}
if err != nil {
if !fatal(err) {
r.db().Exec(`UPDATE files SET fetch_error = ? WHERE id = ?`, err.Error(), it.ID)
}
return fmt.Errorf("%s: %w", a.Name, err)
}
sum := sha256.Sum256(data)
hexsum := hex.EncodeToString(sum[:])
r.downloaded++
if hexsum == lastSum {
// Changed metadata, same bytes: a rename or a new description. The
// version is the same one; it is now known under this chdate.
_, err := r.db().Exec(`UPDATE file_versions SET chdate = ? WHERE file_id = ? AND n = ?`, ch, it.ID, n)
r.db().Exec(`UPDATE files SET fetch_error = NULL WHERE id = ?`, it.ID)
return err
}
tx, err := r.db().Begin()
if err != nil {
return err
}
defer tx.Rollback()
if _, err := tx.Exec(`INSERT INTO blobs (sha256, size, data) VALUES (?, ?, ?) ON CONFLICT DO NOTHING`,
hexsum, len(data), data); err != nil {
return err
}
if _, err := tx.Exec(`INSERT INTO file_versions (file_id, n, sha256, size, chdate, fetched_at) VALUES (?, ?, ?, ?, ?, ?)`,
it.ID, n+1, hexsum, len(data), ch, r.now()); err != nil {
return err
}
if _, err := tx.Exec(`UPDATE files SET fetch_error = NULL WHERE id = ?`, it.ID); err != nil {
return err
}
// A Word document or a presentation is converted as it is stored, so
// that its page only reads; see render.go. The same content is
// converted once.
if converted(a.Name, a.Mime) {
var have int
tx.QueryRow(`SELECT count(*) FROM renders WHERE sha256 = ? AND converter = ?`, hexsum, renderConverter).Scan(&have)
if have == 0 {
if err := storeRender(tx, hexsum, convertFile(a.Name, a.Mime, data), r.now()); err != nil {
return err
}
}
}
return tx.Commit()
}
// ============================================================================
// News
// ============================================================================
// news syncs one range's news: a course, or "studip" for the site-wide ones.
// A news item can be in several ranges, and is only gone from a range it left.
func (r *run) news(ctx context.Context, rangeID, path string) error {
t0 := r.seq
items, _, err := r.s.c.list(ctx, path, nil)
if unavailable(err) {
return nil
}
if err != nil {
return err
}
course := rangeID
if rangeID == "studip" {
course = ""
}
for _, it := range items {
var a struct {
Title string `json:"title"`
Content string `json:"content"`
Mkdate string `json:"mkdate"`
Chdate string `json:"chdate"`
PubStart string `json:"publication-start"`
PubEnd string `json:"publication-end"`
}
if err := it.attrs(&a); err != nil {
return err
}
author := r.userName(ctx, it.rel("author"))
var oldCh sql.NullInt64
err := r.db().QueryRow(`SELECT chdate FROM news WHERE id = ?`, it.ID).Scan(&oldCh)
isNew := errors.Is(err, sql.ErrNoRows)
mk, ch := parseTime(a.Mkdate), parseTime(a.Chdate)
if _, err := r.db().Exec(`INSERT INTO news (id, title, content, author, mkdate, chdate, pub_start, pub_end, first_seen)
VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)
ON CONFLICT (id) DO UPDATE SET title = excluded.title, content = excluded.content,
author = excluded.author, mkdate = excluded.mkdate, chdate = excluded.chdate,
pub_start = excluded.pub_start, pub_end = excluded.pub_end`,
it.ID, a.Title, a.Content, author, mk, ch, parseTime(a.PubStart), parseTime(a.PubEnd), r.now()); err != nil {
return err
}
if _, err := r.db().Exec(`INSERT INTO news_ranges (news_id, range_id, last_seen) VALUES (?, ?, ?)
ON CONFLICT DO UPDATE SET last_seen = excluded.last_seen, gone_at = NULL`, it.ID, rangeID, r.seq); err != nil {
return err
}
switch {
case isNew:
r.record("news", it.ID, course, "new", a.Title, max(mk, parseTime(a.PubStart)))
case oldCh.Int64 != ch:
r.record("news", it.ID, course, "changed", a.Title, ch)
}
}
// News expire by their publication end; that is not a removal worth
// reporting, so leaving a range is recorded without a change entry.
r.db().Exec(`UPDATE news_ranges SET gone_at = ? WHERE range_id = ? AND gone_at IS NULL AND last_seen < ?`,
r.now(), rangeID, t0)
return nil
}
// ============================================================================
// Messages
// ============================================================================
func (r *run) messages(ctx context.Context, userID string) error {
for _, box := range []string{"inbox", "outbox"} {
t0 := r.seq
// The listing carries the whole body. Fetching a message on its own
// is what the website does when it is opened, and may mark it read;
// campusweb never does that.
items, _, err := r.s.c.list(ctx, "/users/"+url.PathEscape(userID)+"/"+box, nil)
if err != nil {
return fmt.Errorf("%s: %w", box, err)
}
for _, it := range items {
var a struct {
Subject string `json:"subject"`
Message string `json:"message"`
Mkdate string `json:"mkdate"`
Priority string `json:"priority"`
}
if err := it.attrs(&a); err != nil {
return err
}
var exists int
r.db().QueryRow(`SELECT 1 FROM messages WHERE id = ?`, it.ID).Scan(&exists)
sender := ""
if box == "inbox" {
sender = r.userName(ctx, it.rel("sender"))
if sender == "" {
sender = "Stud.IP"
}
}
var rcpt []string
for _, u := range it.rels("recipients") {
if u == userID {
continue
}
rcpt = append(rcpt, r.userName(ctx, u))
}
mk := parseTime(a.Mkdate)
if _, err := r.db().Exec(`INSERT INTO messages (id, box, subject, body, sender, recipients, mkdate, priority,
first_seen, last_seen)
VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
ON CONFLICT (id) DO UPDATE SET subject = excluded.subject, body = excluded.body,
sender = excluded.sender, recipients = excluded.recipients, last_seen = excluded.last_seen,
gone_at = NULL`,
it.ID, box, a.Subject, a.Message, sender, strings.Join(rcpt, ", "), mk, a.Priority, r.now(), r.seq); err != nil {
return err
}
if exists == 0 {
title := a.Subject
if box == "outbox" {
title = "(sent) " + title
}
r.record("message", it.ID, "", "new", title, mk)
}
}
// A message deleted on the website is gone there; it stays here, marked.
r.db().Exec(`UPDATE messages SET gone_at = ? WHERE box = ? AND gone_at IS NULL AND last_seen < ?`, r.now(), box, t0)
}
return nil
}
// userName resolves a Stud.IP user id to a name, once per id. "" for no id;
// the id itself when it cannot be resolved, which beats a blank.
func (r *run) userName(ctx context.Context, id string) string {
if id == "" {
return ""
}
if strings.Contains(id, "%system%") {
return "Stud.IP"
}
var name string
if r.db().QueryRow(`SELECT name FROM users WHERE id = ?`, id).Scan(&name) == nil {
return name
}
u, err := r.s.c.get(ctx, "/users/"+url.PathEscape(id))
if err != nil {
if !fatal(err) {
log.Printf("user %s: %v", id, err)
}
return id
}
var a struct {
Name string `json:"formatted-name"`
}
u.attrs(&a)
if a.Name == "" {
return id
}
r.db().Exec(`INSERT INTO users (id, name, fetched_at) VALUES (?, ?, ?) ON CONFLICT DO UPDATE SET name = excluded.name`,
id, a.Name, r.now())
return a.Name
}
// ============================================================================
// Course dates
// ============================================================================
func (r *run) events(ctx context.Context, course string) error {
t0 := r.seq
items, _, err := r.s.c.list(ctx, "/courses/"+url.PathEscape(course)+"/events", nil)
if unavailable(err) {
return nil
}
if err != nil {
return err
}
for _, it := range items {
var a struct {
Title string `json:"title"`
Description string `json:"description"`
Start string `json:"start"`
End string `json:"end"`
Location string `json:"location"`
Categories string `json:"categories"`
Recurrence any `json:"recurrence"`
Cancelled bool `json:"is-cancelled"`
Chdate string `json:"chdate"`
}
if err := it.attrs(&a); err != nil {
return err
}
rec := ""
switch v := a.Recurrence.(type) {
case string:
rec = v
case nil:
default:
b, _ := json.Marshal(v)
rec = string(b)
}
var old struct {
start, end int64
location string
cancelled bool
gone bool
}
var oldLoc sql.NullString
err := r.db().QueryRow(`SELECT start, end, location, cancelled, gone_at IS NOT NULL FROM events WHERE id = ?`, it.ID).
Scan(&old.start, &old.end, &oldLoc, &old.cancelled, &old.gone)
old.location = oldLoc.String
isNew := errors.Is(err, sql.ErrNoRows)
start, end, ch := parseTime(a.Start), parseTime(a.End), parseTime(a.Chdate)
if _, err := r.db().Exec(`INSERT INTO events (id, course_id, title, description, start, end, location, category,
recurrence, cancelled, chdate, first_seen, last_seen)
VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
ON CONFLICT (id) DO UPDATE SET title = excluded.title, description = excluded.description,
start = excluded.start, end = excluded.end, location = excluded.location,
category = excluded.category, recurrence = excluded.recurrence, cancelled = excluded.cancelled,
chdate = excluded.chdate, last_seen = excluded.last_seen, gone_at = NULL`,
it.ID, course, a.Title, a.Description, start, end, a.Location, a.Categories, rec,
a.Cancelled, ch, r.now(), r.seq); err != nil {
return err
}
if isNew {
// A course has a dozen dates from the start; those are the
// course's first sync and quiet. One added later is news.
r.record("event", it.ID, course, "new", "added: "+eventWhen(start, end, a.Location), ch)
continue
}
if old.gone {
r.record("event", it.ID, course, "new", "back: "+eventWhen(start, end, a.Location), ch)
continue
}
for _, d := range eventDiff(old.start, old.end, old.location, old.cancelled, start, end, a.Location, a.Cancelled) {
r.record("event", it.ID, course, "changed", d, ch)
}
}
// A date that disappeared is titled by when it was, since a course's
// dates mostly share one title. Formatted here rather than by SQLite,
// whose localtime is not --timezone.
type goneEvent struct {
id string
start, end int64
loc string
}
rows, err := r.db().Query(`SELECT id, start, end, coalesce(location,'') FROM events
WHERE course_id = ? AND gone_at IS NULL AND last_seen < ?`, course, t0)
if err != nil {
return err
}
var gs []goneEvent
for rows.Next() {
var g goneEvent
rows.Scan(&g.id, &g.start, &g.end, &g.loc)
gs = append(gs, g)
}
rows.Close()
for _, g := range gs {
r.db().Exec(`UPDATE events SET gone_at = ? WHERE id = ?`, r.now(), g.id)
r.record("event", g.id, course, "gone", "removed: "+eventWhen(g.start, g.end, g.loc), 0)
}
return nil
}
// eventDiff names what changed about a date, one entry per change, in the
// words the feed shows. Times are in time.Local, which main sets to
// --timezone.
func eventDiff(oStart, oEnd int64, oLoc string, oCancelled bool, start, end int64, loc string, cancelled bool) []string {
var out []string
switch {
case cancelled && !oCancelled:
return []string{"cancelled: " + eventWhen(start, end, loc)}
case !cancelled && oCancelled:
out = append(out, "no longer cancelled: "+eventWhen(start, end, loc))
}
switch {
case oStart != start:
out = append(out, "moved: "+eventWhen(oStart, oEnd, "")+" → "+eventWhen(start, end, ""))
case oEnd != end:
out = append(out, "time: "+eventWhen(oStart, oEnd, "")+" → "+clockOf(end))
}
if oLoc != loc {
out = append(out, "room: "+orDash(oLoc)+" → "+orDash(loc)+" ("+eventWhen(start, end, "")+")")
}
return out
}
func eventWhen(start, end int64, loc string) string {
s := time.Unix(start, 0).In(time.Local)
w := germanWeekday(s) + " " + s.Format("2006-01-02 15:04")
if end > start {
w += "–" + clockOf(end)
}
if loc != "" {
w += " · " + loc
}
return w
}
func clockOf(t int64) string { return time.Unix(t, 0).In(time.Local).Format("15:04") }
// ============================================================================
// Forum
// ============================================================================
func (r *run) forum(ctx context.Context, course string) error {
t0 := r.seq
topics, _, err := r.s.c.list(ctx, "/courses/"+url.PathEscape(course)+"/forum-topics", nil)
if unavailable(err) {
return nil
}
if err != nil {
return err
}
complete := true
for _, tp := range topics {
var ta struct {
Name string `json:"name"`
}
tp.attrs(&ta)
discs, _, err := r.s.c.list(ctx, "/forum-topics/"+url.PathEscape(tp.ID)+"/discussions", nil)
if err != nil {
if fatal(err) {
return err
}
complete = false
log.Printf("forum topic %s: %v", tp.ID, err)
continue
}
for _, d := range discs {
if err := r.discussion(ctx, course, ta.Name, d); err != nil {
if fatal(err) {
return err
}
complete = false
log.Printf("forum discussion %s: %v", d.ID, err)
}
}
}
if complete {
r.db().Exec(`UPDATE forum_discussions SET gone_at = ? WHERE course_id = ? AND gone_at IS NULL AND last_seen < ?`,
r.now(), course, t0)
}
return nil
}
func (r *run) discussion(ctx context.Context, course, topic string, d resource) error {
var a struct {
Title string `json:"title"`
Mkdate string `json:"mkdate"`
Chdate string `json:"chdate"`
}
var m struct {
Postings int `json:"postings-count"`
Activity string `json:"recent-activity"`
}
if err := d.attrs(&a); err != nil {
return err
}
json.Unmarshal(d.Meta, &m)
act := parseTime(m.Activity)
var oldAct, oldPostings sql.NullInt64
err := r.db().QueryRow(`SELECT activity, postings FROM forum_discussions WHERE id = ?`, d.ID).Scan(&oldAct, &oldPostings)
unchanged := err == nil && oldAct.Int64 == act && oldPostings.Int64 == int64(m.Postings)
if _, err := r.db().Exec(`INSERT INTO forum_discussions (id, course_id, topic, title, mkdate, chdate, activity, postings,
first_seen, last_seen)
VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
ON CONFLICT (id) DO UPDATE SET topic = excluded.topic, title = excluded.title, chdate = excluded.chdate,
activity = excluded.activity, postings = excluded.postings, last_seen = excluded.last_seen, gone_at = NULL`,
d.ID, course, topic, a.Title, parseTime(a.Mkdate), parseTime(a.Chdate), act, m.Postings, r.now(), r.seq); err != nil {
return err
}
if unchanged {
// Reading postings marks them read on Stud.IP; only do it when
// there is something new to read.
return nil
}
t0 := r.seq
q := url.Values{"include": {"author"}}
posts, included, err := r.s.c.list(ctx, "/forum-discussions/"+url.PathEscape(d.ID)+"/postings", q)
if err != nil {
return err
}
authors := map[string]string{}
for _, inc := range included {
var ia struct {
Name string `json:"name"`
}
inc.attrs(&ia)
authors[inc.ID] = ia.Name
}
for _, p := range posts {
var pa struct {
Content string `json:"content"`
Anonymous bool `json:"anonymous"`
Mkdate string `json:"mkdate"`
Chdate string `json:"chdate"`
}
if err := p.attrs(&pa); err != nil {
return err
}
author := authors[p.rel("author")]
if pa.Anonymous {
author = "(anonymous)"
}
var oldCh sql.NullInt64
err := r.db().QueryRow(`SELECT chdate FROM forum_postings WHERE id = ?`, p.ID).Scan(&oldCh)
isNew := errors.Is(err, sql.ErrNoRows)
mk, ch := parseTime(pa.Mkdate), parseTime(pa.Chdate)
if _, err := r.db().Exec(`INSERT INTO forum_postings (id, discussion_id, course_id, author, content, mkdate, chdate,
first_seen, last_seen)
VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)
ON CONFLICT (id) DO UPDATE SET author = excluded.author, content = excluded.content,
chdate = excluded.chdate, last_seen = excluded.last_seen, gone_at = NULL`,
p.ID, d.ID, course, author, pa.Content, mk, ch, r.now(), r.seq); err != nil {
return err
}
switch {
case isNew:
r.record("posting", p.ID, course, "new", a.Title+" — "+author, mk)
case oldCh.Int64 != ch:
r.record("posting", p.ID, course, "changed", a.Title+" — "+author, ch)
}
}
r.db().Exec(`UPDATE forum_postings SET gone_at = ? WHERE discussion_id = ? AND gone_at IS NULL AND last_seen < ?`,
r.now(), d.ID, t0)
return nil
}
// ============================================================================
// Activity stream
// ============================================================================
// activities reads the stream since the last poll and returns the courses it
// names. The cursor is the newest mkdate seen; the stream is filtered by
// time, so the first poll after a long pause reads the whole gap.
func (r *run) activities(ctx context.Context, userID string) ([]string, error) {
since, _ := strconv.ParseInt(getState(r.db(), "activity_since"), 10, 64)
if since == 0 {
// The first poll needs no history: the first full run has just
// read everything there is.
since = r.now() - 14*24*3600
}
q := url.Values{"filter[start]": {strconv.FormatInt(since, 10)}}
items, _, err := r.s.c.list(ctx, "/users/"+url.PathEscape(userID)+"/activitystream", q)
if err != nil {
return nil, fmt.Errorf("activity stream: %w", err)
}
newest := since
seen := map[string]bool{}
var courses []string
for _, it := range items {
var a struct {
Title string `json:"title"`
Mkdate string `json:"mkdate"`
Verb string `json:"verb"`
Type string `json:"activity-type"`
}
if err := it.attrs(&a); err != nil {
return nil, err
}
mk := parseTime(a.Mkdate)
newest = max(newest, mk)
var obj, ctxRel struct {
Data *struct {
Type string `json:"type"`
ID string `json:"id"`
} `json:"data"`
}
json.Unmarshal(it.Relationships["object"], &obj)
json.Unmarshal(it.Relationships["context"], &ctxRel)
var ot, oi, ct, ci string
if obj.Data != nil {
ot, oi = obj.Data.Type, obj.Data.ID
}
if ctxRel.Data != nil {
ct, ci = ctxRel.Data.Type, ctxRel.Data.ID
}
r.db().Exec(`INSERT INTO activities (id, mkdate, type, verb, title, object_type, object_id, context_type, context_id)
VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?) ON CONFLICT DO NOTHING`, it.ID, mk, a.Type, a.Verb, a.Title, ot, oi, ct, ci)
// Who joined a course is most of the stream and changes nothing
// campusweb mirrors.
if ct == "courses" && a.Type != "participants" && !seen[ci] {
seen[ci] = true
courses = append(courses, ci)
}
}
// Equal timestamps are possible; re-reading the newest second is
// harmless (activities are keyed), missing it is not.
setState(r.db(), "activity_since", strconv.FormatInt(newest, 10))
return courses, nil
}
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