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GODT-1146: Refactor header filtering

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This commit is contained in:
James Houlahan
2021-04-30 10:04:41 +02:00
parent ce64aeb05f
commit 0b95ed4dea
14 changed files with 230 additions and 83 deletions
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78
internal/imap/mailbox_fetch.go
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@ -20,9 +20,6 @@ package imap
import (
"bytes"
"context"
"fmt"
"net/textproto"
"sort"
"github.com/ProtonMail/proton-bridge/internal/imap/cache"
"github.com/ProtonMail/proton-bridge/pkg/message"
@ -53,7 +50,7 @@ func (im *imapMailbox) getMessage(
case imap.FetchEnvelope:
// No need to check IsFullHeaderCached here. API header
// contain enough information to build the envelope.
msg.Envelope = message.GetEnvelope(m, storeMessage.GetHeader())
msg.Envelope = message.GetEnvelope(m, storeMessage.GetMIMEHeader())
case imap.FetchBody, imap.FetchBodyStructure:
structure, err := im.getBodyStructure(storeMessage)
if err != nil {
@ -238,30 +235,31 @@ func isMessageInDraftFolder(m *pmapi.Message) bool {
// This will download message (or read from cache) and pick up the section,
// extract data (header,body, both) and trim the output if needed.
func (im *imapMailbox) getMessageBodySection( //nolint[funlen]
//
// In order to speed up (avoid download and decryptions) we
// cache the header. If a mail header was requested and DB
// contains full header (it means it was already built once)
// the DB header can be used without downloading and decrypting.
// Otherwise header is incomplete and clients would have issues
// e.g. AppleMail expects `text/plain` in HTML mails.
//
// For all other cases it is necessary to download and decrypt the message
// and drop the header which was obtained from cache. The header will
// will be stored in DB once successfully built. Check `getBodyAndStructure`.
func (im *imapMailbox) getMessageBodySection(
storeMessage storeMessageProvider,
section *imap.BodySectionName,
msgBuildCountHistogram *msgBuildCountHistogram,
) (imap.Literal, error) {
var header textproto.MIMEHeader
var extraNewlineAfterHeader bool
var header []byte
var response []byte
im.log.WithField("msgID", storeMessage.ID()).Trace("Getting message body")
isMainHeaderRequested := len(section.Path) == 0 && section.Specifier == imap.HeaderSpecifier
if isMainHeaderRequested && storeMessage.IsFullHeaderCached() {
// In order to speed up (avoid download and decryptions) we
// cache the header. If a mail header was requested and DB
// contains full header (it means it was already built once)
// the DB header can be used without downloading and decrypting.
// Otherwise header is incomplete and clients would have issues
// e.g. AppleMail expects `text/plain` in HTML mails.
header = storeMessage.GetHeader()
} else {
// For all other cases it is necessary to download and decrypt the message
// and drop the header which was obtained from cache. The header will
// will be stored in DB once successfully built. Check `getBodyAndStructure`.
structure, bodyReader, err := im.getBodyAndStructure(storeMessage, msgBuildCountHistogram)
if err != nil {
return nil, err
@ -278,10 +276,7 @@ func (im *imapMailbox) getMessageBodySection( //nolint[funlen]
case section.Specifier == imap.MIMESpecifier: // The MIME part specifier refers to the [MIME-IMB] header for this part.
fallthrough
case section.Specifier == imap.HeaderSpecifier:
if content, err := structure.GetSectionContent(bodyReader, section.Path); err == nil && content != nil {
extraNewlineAfterHeader = true
}
header, err = structure.GetSectionHeader(section.Path)
header, err = structure.GetSectionHeaderBytes(bodyReader, section.Path)
default:
err = errors.New("Unknown specifier " + string(section.Specifier))
}
@ -292,54 +287,13 @@ func (im *imapMailbox) getMessageBodySection( //nolint[funlen]
}
if header != nil {
response = filteredHeaderAsBytes(header, section)
// The blank line is included in all header fetches,
// except in the case of a message which has no body.
if extraNewlineAfterHeader {
response = append(response, []byte("\r\n")...)
}
response = filterHeader(header, section)
}
// Trim any output if requested.
return bytes.NewBuffer(section.ExtractPartial(response)), nil
}
// filteredHeaderAsBytes filters the header fields by section fields and it
// returns the filtered fields as bytes.
// Options are: all fields, only selected fields, all fields except selected.
func filteredHeaderAsBytes(header textproto.MIMEHeader, section *imap.BodySectionName) []byte {
// remove fields
if len(section.Fields) != 0 && section.NotFields {
for _, field := range section.Fields {
header.Del(field)
}
}
fields := make([]string, 0, len(header))
if len(section.Fields) == 0 || section.NotFields { // add all and sort
for f := range header {
fields = append(fields, f)
}
sort.Strings(fields)
} else { // add only requested (in requested order)
for _, f := range section.Fields {
fields = append(fields, textproto.CanonicalMIMEHeaderKey(f))
}
}
headerBuf := &bytes.Buffer{}
for _, canonical := range fields {
if values, ok := header[canonical]; !ok {
continue
} else {
for _, val := range values {
fmt.Fprintf(headerBuf, "%s: %s\r\n", canonical, val)
}
}
}
return headerBuf.Bytes()
}
// buildMessage from PM to IMAP.
func (im *imapMailbox) buildMessage(m *pmapi.Message) (*message.BodyStructure, []byte, error) {
body, err := im.builder.NewJobWithOptions(