github.com/google/trillian-examples@v0.0.0-20240520080811-0d40d35cef0e/binary_transparency/firmware/internal/client/wclient.go (about)

     1  // Copyright 2021 Google LLC. All Rights Reserved.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package client
    16  
    17  import (
    18  	"fmt"
    19  	"io"
    20  	"net/http"
    21  	"net/url"
    22  
    23  	"github.com/golang/glog"
    24  	"github.com/google/trillian-examples/binary_transparency/firmware/api"
    25  	"golang.org/x/mod/sumdb/note"
    26  	"google.golang.org/grpc/status"
    27  )
    28  
    29  // WitnessClient is an HTTP client for the FT witness.
    30  type WitnessClient struct {
    31  	// URL is the base URL for the FT witness.
    32  	URL            *url.URL
    33  	LogSigVerifier note.Verifier
    34  }
    35  
    36  // GetWitnessCheckpoint returns a checkpoint from witness server
    37  func (c WitnessClient) GetWitnessCheckpoint() (*api.LogCheckpoint, error) {
    38  	u, err := c.URL.Parse(api.WitnessGetCheckpoint)
    39  	if err != nil {
    40  		return nil, err
    41  	}
    42  	r, err := http.Get(u.String())
    43  	if err != nil {
    44  		return nil, err
    45  	}
    46  	defer func() {
    47  		if err := r.Body.Close(); err != nil {
    48  			glog.Errorf("r.Body.Close(): %v", err)
    49  		}
    50  	}()
    51  	if r.StatusCode != 200 {
    52  		return nil, errFromRsp("failed to fetch checkpoint", r)
    53  	}
    54  
    55  	b, err := io.ReadAll(r.Body)
    56  	if err != nil {
    57  		return nil, fmt.Errorf("failed to read body: %w", err)
    58  	}
    59  	return api.ParseCheckpoint(b, c.LogSigVerifier)
    60  }
    61  
    62  func errFromRsp(m string, r *http.Response) error {
    63  	if r.StatusCode == 200 {
    64  		return nil
    65  	}
    66  
    67  	b, _ := io.ReadAll(r.Body) // Ignore any error, we want to ensure we return the right status code which we already know.
    68  
    69  	msg := fmt.Sprintf("%s: %s", m, string(b))
    70  	return status.New(codeFromHTTPResponse(r.StatusCode), msg).Err()
    71  }