ooni-probe-cli/internal/engine/legacy/netx/oldhttptransport/bodytracer.go
Simone Basso 0fdc9cafb5
fix(all): introduce and use iox.ReadAllContext (#379)
* fix(all): introduce and use iox.ReadAllContext

This improvement over the ioutil.ReadAll utility returns early
if the context expires. This enables us to unblock stuck code in
case there's censorship confounding the TCP stack.

See https://github.com/ooni/probe/issues/1417.

Compared to the functionality postulated in the above mentioned
issue, I choose to be more generic and separate limiting the
maximum body size (not implemented here) from using the context
to return early when reading a body (or any other reader).

After implementing iox.ReadAllContext, I made sure we always
use it everywhere in the tree instead of ioutil.ReadAll.

This includes many parts of the codebase where in theory we don't
need iox.ReadAllContext. Though, changing all the places makes
checking whether we're not using ioutil.ReadAll where we should
not be using it easy: `git grep` should return no lines.

* Update internal/iox/iox_test.go

* fix(ndt7): treat context errors as non-errors

The rationale is explained by the comment documenting reduceErr.

* Update internal/engine/experiment/ndt7/download.go
2021-06-15 11:57:40 +02:00

83 lines
2.2 KiB
Go

package oldhttptransport
import (
"io"
"net/http"
"time"
"github.com/ooni/probe-cli/v3/internal/engine/legacy/netx/modelx"
"github.com/ooni/probe-cli/v3/internal/engine/legacy/netx/transactionid"
)
// BodyTracer performs single HTTP transactions and emits
// measurement events as they happen.
type BodyTracer struct {
Transport http.RoundTripper
}
// NewBodyTracer creates a new Transport.
func NewBodyTracer(roundTripper http.RoundTripper) *BodyTracer {
return &BodyTracer{Transport: roundTripper}
}
// RoundTrip executes a single HTTP transaction, returning
// a Response for the provided Request.
func (t *BodyTracer) RoundTrip(req *http.Request) (resp *http.Response, err error) {
resp, err = t.Transport.RoundTrip(req)
if err != nil {
return
}
// "The http Client and Transport guarantee that Body is always
// non-nil, even on responses without a body or responses with
// a zero-length body." (from the docs)
resp.Body = &bodyWrapper{
ReadCloser: resp.Body,
root: modelx.ContextMeasurementRootOrDefault(req.Context()),
tid: transactionid.ContextTransactionID(req.Context()),
}
return
}
// CloseIdleConnections closes the idle connections.
func (t *BodyTracer) CloseIdleConnections() {
// Adapted from net/http code
type closeIdler interface {
CloseIdleConnections()
}
if tr, ok := t.Transport.(closeIdler); ok {
tr.CloseIdleConnections()
}
}
type bodyWrapper struct {
io.ReadCloser
root *modelx.MeasurementRoot
tid int64
}
func (bw *bodyWrapper) Read(b []byte) (n int, err error) {
n, err = bw.ReadCloser.Read(b)
bw.root.Handler.OnMeasurement(modelx.Measurement{
HTTPResponseBodyPart: &modelx.HTTPResponseBodyPartEvent{
// "Read reads up to len(p) bytes into p. It returns the number of
// bytes read (0 <= n <= len(p)) and any error encountered."
Data: b[:n],
Error: err,
DurationSinceBeginning: time.Since(bw.root.Beginning),
TransactionID: bw.tid,
},
})
return
}
func (bw *bodyWrapper) Close() (err error) {
err = bw.ReadCloser.Close()
bw.root.Handler.OnMeasurement(modelx.Measurement{
HTTPResponseDone: &modelx.HTTPResponseDoneEvent{
DurationSinceBeginning: time.Since(bw.root.Beginning),
TransactionID: bw.tid,
},
})
return
}