75 lines
1.9 KiB
Go
75 lines
1.9 KiB
Go
package rpc
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import (
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"bytes"
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"encoding/json"
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"net/http"
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"reflect"
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"sync/atomic"
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"github.com/pkg/errors"
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)
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// Client implements remote engine and delegates all calls to remote http server
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type Client struct {
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API string
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Client http.Client
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AuthUser string
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AuthPasswd string
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id uint64
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}
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// Call remote server with given method and arguments
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func (r *Client) Call(method string, args ...interface{}) (*Response, error) {
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var b []byte
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var err error
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switch {
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case len(args) == 0:
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b, err = json.Marshal(Request{Method: method, ID: atomic.AddUint64(&r.id, 1)})
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if err != nil {
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return nil, errors.Wrapf(err, "marshaling failed for %s", method)
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}
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case len(args) == 1 && reflect.TypeOf(args[0]).Kind() == reflect.Struct:
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b, err = json.Marshal(Request{Method: method, Params: args[0], ID: atomic.AddUint64(&r.id, 1)})
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if err != nil {
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return nil, errors.Wrapf(err, "marshaling failed for %s", method)
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}
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default:
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b, err = json.Marshal(Request{Method: method, Params: args, ID: atomic.AddUint64(&r.id, 1)})
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if err != nil {
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return nil, errors.Wrapf(err, "marshaling failed for %s", method)
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}
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}
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req, err := http.NewRequest("POST", r.API, bytes.NewBuffer(b))
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if err != nil {
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return nil, errors.Wrapf(err, "failed to make request for %s", method)
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}
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req.Header.Set("Content-Type", "application/json; charset=utf-8")
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if r.AuthUser != "" && r.AuthPasswd != "" {
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req.SetBasicAuth(r.AuthUser, r.AuthPasswd)
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}
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resp, err := r.Client.Do(req)
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if err != nil {
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return nil, errors.Wrapf(err, "remote call failed for %s", method)
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}
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defer resp.Body.Close()
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if resp.StatusCode != 200 {
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return nil, errors.Errorf("bad status %s for %s", resp.Status, method)
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}
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cr := Response{}
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if err = json.NewDecoder(resp.Body).Decode(&cr); err != nil {
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return nil, errors.Wrapf(err, "failed to decode response for %s", method)
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}
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if cr.Error != "" {
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return nil, errors.New(cr.Error)
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}
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return &cr, nil
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}
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