120 lines
2.2 KiB
Go
120 lines
2.2 KiB
Go
package serv
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import (
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"fmt"
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"io/ioutil"
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"net/http"
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"strings"
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"github.com/cespare/xxhash/v2"
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"github.com/dosco/super-graph/psql"
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)
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var (
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rmap map[uint64]*resolvFn
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)
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type resolvFn struct {
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IDField []byte
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Path [][]byte
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Fn func(r *http.Request, id []byte) ([]byte, error)
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}
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func initResolvers() {
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rmap = make(map[uint64]*resolvFn)
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for _, t := range conf.DB.Tables {
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initRemotes(t)
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}
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}
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func initRemotes(t configTable) {
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h := xxhash.New()
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for _, r := range t.Remotes {
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// defines the table column to be used as an id in the
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// remote request
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idcol := r.ID
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// if no table column specified in the config then
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// use the primary key of the table as the id
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if len(idcol) == 0 {
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idcol = pcompile.IDColumn(t.Name)
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}
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idk := fmt.Sprintf("__%s_%s", t.Name, idcol)
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// register a relationship between the remote data
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// and the database table
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h.WriteString(strings.ToLower(r.Name))
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h.WriteString(t.Name)
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key := h.Sum64()
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h.Reset()
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val := &psql.DBRel{
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Type: psql.RelRemote,
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Col1: idcol,
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Col2: idk,
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}
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pcompile.AddRelationship(key, val)
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// the function thats called to resolve this remote
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// data request
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fn := buildFn(r)
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path := [][]byte{}
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for _, p := range strings.Split(r.Path, ".") {
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path = append(path, []byte(p))
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}
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rf := &resolvFn{
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IDField: []byte(idk),
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Path: path,
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Fn: fn,
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}
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// index resolver obj by parent and child names
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rmap[mkkey(h, r.Name, t.Name)] = rf
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// index resolver obj by IDField
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rmap[xxhash.Sum64(rf.IDField)] = rf
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}
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}
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func buildFn(r configRemote) func(*http.Request, []byte) ([]byte, error) {
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reqURL := strings.Replace(r.URL, "$id", "%s", 1)
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client := &http.Client{}
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h := make(http.Header, len(r.PassHeaders))
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for _, v := range r.SetHeaders {
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h.Set(v.Name, v.Value)
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}
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fn := func(inReq *http.Request, id []byte) ([]byte, error) {
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req, err := http.NewRequest("GET", fmt.Sprintf(reqURL, id), nil)
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if err != nil {
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return nil, err
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}
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for _, v := range r.PassHeaders {
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h.Set(v, inReq.Header.Get(v))
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}
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req.Header = h
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res, err := client.Do(req)
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if err != nil {
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return nil, err
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}
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defer res.Body.Close()
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b, err := ioutil.ReadAll(res.Body)
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if err != nil {
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return nil, err
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}
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return b, nil
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}
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return fn
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}
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