super-graph/serv/core.go
2019-09-08 01:54:38 -04:00

485 lines
8.6 KiB
Go

package serv
import (
"bytes"
"context"
"encoding/json"
"errors"
"fmt"
"io"
"net/http"
"os"
"sync"
"time"
"github.com/cespare/xxhash/v2"
"github.com/dosco/super-graph/jsn"
"github.com/dosco/super-graph/psql"
"github.com/dosco/super-graph/qcode"
"github.com/go-pg/pg"
"github.com/valyala/fasttemplate"
)
const (
empty = ""
)
type coreContext struct {
req gqlReq
res gqlResp
context.Context
}
func (c *coreContext) handleReq(w io.Writer, req *http.Request) error {
var err error
var skipped uint32
var qc *qcode.QCode
var data []byte
c.req.ref = req.Referer()
//conf.UseAllowList = true
if conf.UseAllowList {
var ps *preparedItem
data, ps, err = c.resolvePreparedSQL(c.req.Query)
if err != nil {
return err
}
skipped = ps.skipped
qc = ps.qc
} else {
qc, err = qcompile.Compile([]byte(c.req.Query))
if err != nil {
return err
}
data, skipped, err = c.resolveSQL(qc)
if err != nil {
return err
}
}
if len(data) == 0 || skipped == 0 {
return c.render(w, data)
}
sel := qc.Selects
h := xxhash.New()
// fetch the field name used within the db response json
// that are used to mark insertion points and the mapping between
// those field names and their select objects
fids, sfmap := parentFieldIds(h, sel, skipped)
// fetch the field values of the marked insertion points
// these values contain the id to be used with fetching remote data
from := jsn.Get(data, fids)
var to []jsn.Field
switch {
case len(from) == 1:
to, err = c.resolveRemote(req, h, from[0], sel, sfmap)
case len(from) > 1:
to, err = c.resolveRemotes(req, h, from, sel, sfmap)
default:
return errors.New("something wrong no remote ids found in db response")
}
if err != nil {
return err
}
var ob bytes.Buffer
err = jsn.Replace(&ob, data, from, to)
if err != nil {
return err
}
return c.render(w, ob.Bytes())
}
func (c *coreContext) resolveRemote(
req *http.Request,
h *xxhash.Digest,
field jsn.Field,
sel []qcode.Select,
sfmap map[uint64]*qcode.Select) ([]jsn.Field, error) {
// replacement data for the marked insertion points
// key and value will be replaced by whats below
toA := [1]jsn.Field{}
to := toA[:1]
// use the json key to find the related Select object
k1 := xxhash.Sum64(field.Key)
s, ok := sfmap[k1]
if !ok {
return nil, nil
}
p := sel[s.ParentID]
// then use the Table nme in the Select and it's parent
// to find the resolver to use for this relationship
k2 := mkkey(h, s.Table, p.Table)
r, ok := rmap[k2]
if !ok {
return nil, nil
}
id := jsn.Value(field.Value)
if len(id) == 0 {
return nil, nil
}
st := time.Now()
b, err := r.Fn(req, id)
if err != nil {
return nil, err
}
if conf.EnableTracing {
c.addTrace(sel, s.ID, st)
}
if len(r.Path) != 0 {
b = jsn.Strip(b, r.Path)
}
var ob bytes.Buffer
if len(s.Cols) != 0 {
err = jsn.Filter(&ob, b, colsToList(s.Cols))
if err != nil {
return nil, err
}
} else {
ob.WriteString("null")
}
to[0] = jsn.Field{[]byte(s.FieldName), ob.Bytes()}
return to, nil
}
func (c *coreContext) resolveRemotes(
req *http.Request,
h *xxhash.Digest,
from []jsn.Field,
sel []qcode.Select,
sfmap map[uint64]*qcode.Select) ([]jsn.Field, error) {
// replacement data for the marked insertion points
// key and value will be replaced by whats below
to := make([]jsn.Field, len(from))
var wg sync.WaitGroup
wg.Add(len(from))
var cerr error
for i, id := range from {
// use the json key to find the related Select object
k1 := xxhash.Sum64(id.Key)
s, ok := sfmap[k1]
if !ok {
return nil, nil
}
p := sel[s.ParentID]
// then use the Table nme in the Select and it's parent
// to find the resolver to use for this relationship
k2 := mkkey(h, s.Table, p.Table)
r, ok := rmap[k2]
if !ok {
return nil, nil
}
id := jsn.Value(id.Value)
if len(id) == 0 {
return nil, nil
}
go func(n int, id []byte, s *qcode.Select) {
defer wg.Done()
st := time.Now()
b, err := r.Fn(req, id)
if err != nil {
cerr = fmt.Errorf("%s: %s", s.Table, err)
return
}
if conf.EnableTracing {
c.addTrace(sel, s.ID, st)
}
if len(r.Path) != 0 {
b = jsn.Strip(b, r.Path)
}
var ob bytes.Buffer
if len(s.Cols) != 0 {
err = jsn.Filter(&ob, b, colsToList(s.Cols))
if err != nil {
cerr = fmt.Errorf("%s: %s", s.Table, err)
return
}
} else {
ob.WriteString("null")
}
to[n] = jsn.Field{[]byte(s.FieldName), ob.Bytes()}
}(i, id, s)
}
wg.Wait()
return to, cerr
}
func (c *coreContext) resolvePreparedSQL(gql string) ([]byte, *preparedItem, error) {
ps, ok := _preparedList[gqlHash(gql, c.req.Vars)]
if !ok {
return nil, nil, errUnauthorized
}
var root json.RawMessage
vars := varList(c, ps.args)
tx, err := db.Begin()
if err != nil {
return nil, nil, err
}
defer tx.Rollback()
if v := c.Value(userIDKey); v != nil {
_, err = tx.Exec(`SET LOCAL SESSION "user.id" = ?`, v)
if err != nil {
return nil, nil, err
}
}
_, err = tx.Stmt(ps.stmt).QueryOne(pg.Scan(&root), vars...)
if err != nil {
return nil, nil, err
}
if err := tx.Commit(); err != nil {
return nil, nil, err
}
// w.WriteString(`SET LOCAL SESSION "user.id" = '{{user_id}}'; `)
fmt.Printf("PRE: %v\n", ps.stmt)
return []byte(root), ps, nil
}
func (c *coreContext) resolveSQL(qc *qcode.QCode) (
[]byte, uint32, error) {
stmt := &bytes.Buffer{}
vars := make(map[string]json.RawMessage)
if err := json.Unmarshal(c.req.Vars, &vars); err != nil {
return nil, 0, err
}
skipped, err := pcompile.Compile(qc, stmt, psql.Variables(vars))
if err != nil {
return nil, 0, err
}
t := fasttemplate.New(stmt.String(), openVar, closeVar)
stmt.Reset()
_, err = t.ExecuteFunc(stmt, varMap(c))
if err == errNoUserID &&
authFailBlock == authFailBlockPerQuery &&
authCheck(c) == false {
return nil, 0, errUnauthorized
}
if err != nil {
return nil, 0, err
}
finalSQL := stmt.String()
if conf.LogLevel == "debug" {
os.Stdout.WriteString(finalSQL)
}
var st time.Time
if conf.EnableTracing {
st = time.Now()
}
tx, err := db.Begin()
if err != nil {
return nil, 0, err
}
defer tx.Rollback()
if v := c.Value(userIDKey); v != nil {
_, err = tx.Exec(`SET LOCAL SESSION "user.id" = ?`, v)
if err != nil {
return nil, 0, err
}
}
fmt.Printf("RAW: %#v\n", finalSQL)
var root json.RawMessage
_, err = tx.QueryOne(pg.Scan(&root), finalSQL)
if err != nil {
return nil, 0, err
}
if err := tx.Commit(); err != nil {
return nil, 0, err
}
if conf.EnableTracing && len(qc.Selects) != 0 {
c.addTrace(
qc.Selects,
qc.Selects[0].ID,
st)
}
if conf.UseAllowList == false {
_allowList.add(&c.req)
}
return []byte(root), skipped, nil
}
func (c *coreContext) render(w io.Writer, data []byte) error {
c.res.Data = json.RawMessage(data)
return json.NewEncoder(w).Encode(c.res)
}
func (c *coreContext) addTrace(sel []qcode.Select, id int32, st time.Time) {
et := time.Now()
du := et.Sub(st)
if c.res.Extensions == nil {
c.res.Extensions = &extensions{&trace{
Version: 1,
StartTime: st,
Execution: execution{},
}}
}
c.res.Extensions.Tracing.EndTime = et
c.res.Extensions.Tracing.Duration = du
n := 1
for i := id; i != 0; i = sel[i].ParentID {
n++
}
path := make([]string, n)
n--
for i := id; ; i = sel[i].ParentID {
path[n] = sel[i].Table
if sel[i].ID == 0 {
break
}
n--
}
tr := resolver{
Path: path,
ParentType: "Query",
FieldName: sel[id].Table,
ReturnType: "object",
StartOffset: 1,
Duration: du,
}
c.res.Extensions.Tracing.Execution.Resolvers =
append(c.res.Extensions.Tracing.Execution.Resolvers, tr)
}
func parentFieldIds(h *xxhash.Digest, sel []qcode.Select, skipped uint32) (
[][]byte,
map[uint64]*qcode.Select) {
c := 0
for i := range sel {
s := &sel[i]
if isSkipped(skipped, uint32(s.ID)) {
c++
}
}
// list of keys (and it's related value) to extract from
// the db json response
fm := make([][]byte, c)
// mapping between the above extracted key and a Select
// object
sm := make(map[uint64]*qcode.Select, c)
n := 0
for i := range sel {
s := &sel[i]
if isSkipped(skipped, uint32(s.ID)) == false {
continue
}
p := sel[s.ParentID]
k := mkkey(h, s.Table, p.Table)
if r, ok := rmap[k]; ok {
fm[n] = r.IDField
n++
k := xxhash.Sum64(r.IDField)
sm[k] = s
}
}
return fm, sm
}
func isSkipped(n uint32, pos uint32) bool {
return ((n & (1 << pos)) != 0)
}
func authCheck(ctx *coreContext) bool {
return (ctx.Value(userIDKey) != nil)
}
func colsToList(cols []qcode.Column) []string {
var f []string
for i := range cols {
f = append(f, cols[i].Name)
}
return f
}