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parse-requirements-txt.go
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parse-requirements-txt.go
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package lockfile
import (
"bufio"
"fmt"
"path/filepath"
"strings"
"github.com/google/osv-scanner/internal/cachedregexp"
)
const PipEcosystem Ecosystem = "PyPI"
// todo: expand this to support more things, e.g.
//
// https://pip.pypa.io/en/stable/reference/requirements-file-format/#example
func parseLine(line string) PackageDetails {
var constraint string
name := line
version := "0.0.0"
if strings.Contains(line, "==") {
constraint = "=="
}
if strings.Contains(line, ">=") {
constraint = ">="
}
if strings.Contains(line, "~=") {
constraint = "~="
}
if strings.Contains(line, "!=") {
constraint = "!="
}
if constraint != "" {
unprocessedName, unprocessedVersion, _ := strings.Cut(line, constraint)
name = strings.TrimSpace(unprocessedName)
if constraint != "!=" {
version, _, _ = strings.Cut(strings.TrimSpace(unprocessedVersion), " ")
}
}
return PackageDetails{
Name: normalizedRequirementName(name),
Version: version,
Ecosystem: PipEcosystem,
CompareAs: PipEcosystem,
}
}
// normalizedName ensures that the package name is normalized per PEP-0503
// and then removing "added support" syntax if present.
//
// This is done to ensure we don't miss any advisories, as while the OSV
// specification says that the normalized name should be used for advisories,
// that's not the case currently in our databases, _and_ Pip itself supports
// non-normalized names in the requirements.txt, so we need to normalize
// on both sides to ensure we don't have false negatives.
//
// It's possible that this will cause some false positives, but that is better
// than false negatives, and can be dealt with when/if it actually happens.
func normalizedRequirementName(name string) string {
// per https://www.python.org/dev/peps/pep-0503/#normalized-names
name = cachedregexp.MustCompile(`[-_.]+`).ReplaceAllString(name, "-")
name = strings.ToLower(name)
name, _, _ = strings.Cut(name, "[")
return name
}
func removeComments(line string) string {
var re = cachedregexp.MustCompile(`(^|\s+)#.*$`)
return strings.TrimSpace(re.ReplaceAllString(line, ""))
}
func isNotRequirementLine(line string) bool {
return line == "" ||
// flags are not supported
strings.HasPrefix(line, "-") ||
// file urls
strings.HasPrefix(line, "https://") ||
strings.HasPrefix(line, "http://") ||
// file paths are not supported (relative or absolute)
strings.HasPrefix(line, ".") ||
strings.HasPrefix(line, "/")
}
func isLineContinuation(line string) bool {
// checks that the line ends with an odd number of back slashes,
// meaning the last one isn't escaped
var re = cachedregexp.MustCompile(`([^\\]|^)(\\{2})*\\$`)
return re.MatchString(line)
}
type RequirementsTxtExtractor struct{}
func (e RequirementsTxtExtractor) ShouldExtract(path string) bool {
return filepath.Base(path) == "requirements.txt"
}
func (e RequirementsTxtExtractor) Extract(f DepFile) ([]PackageDetails, error) {
return parseRequirementsTxt(f, map[string]struct{}{})
}
func parseRequirementsTxt(f DepFile, requiredAlready map[string]struct{}) ([]PackageDetails, error) {
packages := map[string]PackageDetails{}
group := strings.TrimSuffix(filepath.Base(f.Path()), filepath.Ext(f.Path()))
hasGroup := func(groups []string) bool {
for _, g := range groups {
if g == group {
return true
}
}
return false
}
scanner := bufio.NewScanner(f)
for scanner.Scan() {
line := scanner.Text()
for isLineContinuation(line) {
line = strings.TrimSuffix(line, "\\")
if scanner.Scan() {
line += scanner.Text()
}
}
line = removeComments(line)
if ar := strings.TrimPrefix(line, "-r "); ar != line {
err := func() error {
af, err := f.Open(ar)
if err != nil {
return fmt.Errorf("failed to include %s: %w", line, err)
}
defer af.Close()
if _, ok := requiredAlready[af.Path()]; ok {
return nil
}
requiredAlready[af.Path()] = struct{}{}
details, err := parseRequirementsTxt(af, requiredAlready)
if err != nil {
return fmt.Errorf("failed to include %s: %w", line, err)
}
for _, detail := range details {
packages[detail.Name+"@"+detail.Version] = detail
}
return nil
}()
if err != nil {
return []PackageDetails{}, err
}
continue
}
if isNotRequirementLine(line) {
continue
}
detail := parseLine(line)
key := detail.Name + "@" + detail.Version
if _, ok := packages[key]; !ok {
packages[key] = detail
}
d := packages[key]
if !hasGroup(d.DepGroups) {
d.DepGroups = append(d.DepGroups, group)
packages[key] = d
}
}
if err := scanner.Err(); err != nil {
return []PackageDetails{}, fmt.Errorf("error while scanning %s: %w", f.Path(), err)
}
return pkgDetailsMapToSlice(packages), nil
}
var _ Extractor = RequirementsTxtExtractor{}
//nolint:gochecknoinits
func init() {
registerExtractor("requirements.txt", RequirementsTxtExtractor{})
}
func ParseRequirementsTxt(pathToLockfile string) ([]PackageDetails, error) {
return extractFromFile(pathToLockfile, RequirementsTxtExtractor{})
}