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parsing.go
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parsing.go
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package parse
import (
"net"
"os"
"path/filepath"
"strings"
)
type parser struct {
Dispenser
block ServerBlock // current server block being parsed
eof bool // if we encounter a valid EOF in a hard place
}
func (p *parser) parseAll() ([]ServerBlock, error) {
var blocks []ServerBlock
for p.Next() {
err := p.parseOne()
if err != nil {
return blocks, err
}
if len(p.block.Addresses) > 0 {
blocks = append(blocks, p.block)
}
}
return blocks, nil
}
func (p *parser) parseOne() error {
p.block = ServerBlock{Tokens: make(map[string][]token)}
err := p.begin()
if err != nil {
return err
}
return nil
}
func (p *parser) begin() error {
if len(p.tokens) == 0 {
return nil
}
err := p.addresses()
if err != nil {
return err
}
if p.eof {
// this happens if the Caddyfile consists of only
// a line of addresses and nothing else
return nil
}
err = p.blockContents()
if err != nil {
return err
}
return nil
}
func (p *parser) addresses() error {
var expectingAnother bool
for {
tkn := p.Val()
// special case: import directive replaces tokens during parse-time
if tkn == "import" && p.isNewLine() {
err := p.doImport()
if err != nil {
return err
}
continue
}
// Open brace definitely indicates end of addresses
if tkn == "{" {
if expectingAnother {
return p.Errf("Expected another address but had '%s' - check for extra comma", tkn)
}
break
}
if tkn != "" {
// Trailing comma indicates another address will follow, which
// may possibly be on the next line
if tkn[len(tkn)-1] == ',' {
tkn = tkn[:len(tkn)-1]
expectingAnother = true
} else {
expectingAnother = false // but we may still see another one on this line
}
// Parse and save this address
host, port, err := standardAddress(tkn)
if err != nil {
return err
}
p.block.Addresses = append(p.block.Addresses, Address{host, port})
}
// Advance token and possibly break out of loop or return error
hasNext := p.Next()
if expectingAnother && !hasNext {
return p.EofErr()
}
if !hasNext {
p.eof = true
break // EOF
}
if !expectingAnother && p.isNewLine() {
break
}
}
return nil
}
func (p *parser) blockContents() error {
errOpenCurlyBrace := p.openCurlyBrace()
if errOpenCurlyBrace != nil {
// single-server configs don't need curly braces
p.cursor--
}
err := p.directives()
if err != nil {
return err
}
// Only look for close curly brace if there was an opening
if errOpenCurlyBrace == nil {
err = p.closeCurlyBrace()
if err != nil {
return err
}
}
return nil
}
// directives parses through all the lines for directives
// and it expects the next token to be the first
// directive. It goes until EOF or closing curly brace
// which ends the server block.
func (p *parser) directives() error {
for p.Next() {
// end of server block
if p.Val() == "}" {
break
}
// special case: import directive replaces tokens during parse-time
if p.Val() == "import" {
err := p.doImport()
if err != nil {
return err
}
p.cursor-- // cursor is advanced when we continue, so roll back one more
continue
}
// normal case: parse a directive on this line
if err := p.directive(); err != nil {
return err
}
}
return nil
}
// doImport swaps out the import directive and its argument
// (a total of 2 tokens) with the tokens in the file specified.
// When the function returns, the cursor is on the token before
// where the import directive was. In other words, call Next()
// to access the first token that was imported.
func (p *parser) doImport() error {
if !p.NextArg() {
return p.ArgErr()
}
importFile := p.Val()
if p.NextArg() {
return p.Err("Import allows only one file to import")
}
file, err := os.Open(importFile)
if err != nil {
return p.Errf("Could not import %s - %v", importFile, err)
}
defer file.Close()
importedTokens := allTokens(file)
// Tack the filename onto these tokens so any errors show the imported file's name
for i := 0; i < len(importedTokens); i++ {
importedTokens[i].file = filepath.Base(importFile)
}
// Splice out the import directive and its argument (2 tokens total)
// and insert the imported tokens in their place.
tokensBefore := p.tokens[:p.cursor-1]
tokensAfter := p.tokens[p.cursor+1:]
p.tokens = append(tokensBefore, append(importedTokens, tokensAfter...)...)
p.cursor-- // cursor was advanced one position to read the filename; rewind it
return nil
}
// directive collects tokens until the directive's scope
// closes (either end of line or end of curly brace block).
// It expects the currently-loaded token to be a directive
// (or } that ends a server block). The collected tokens
// are loaded into the current server block for later use
// by directive setup functions.
func (p *parser) directive() error {
dir := p.Val()
nesting := 0
if _, ok := ValidDirectives[dir]; !ok {
return p.Errf("Unknown directive '%s'", dir)
}
// The directive itself is appended as a relevant token
p.block.Tokens[dir] = append(p.block.Tokens[dir], p.tokens[p.cursor])
for p.Next() {
if p.Val() == "{" {
nesting++
} else if p.isNewLine() && nesting == 0 {
p.cursor-- // read too far
break
} else if p.Val() == "}" && nesting > 0 {
nesting--
} else if p.Val() == "}" && nesting == 0 {
return p.Err("Unexpected '}' because no matching opening brace")
}
p.block.Tokens[dir] = append(p.block.Tokens[dir], p.tokens[p.cursor])
}
if nesting > 0 {
return p.EofErr()
}
return nil
}
// openCurlyBrace expects the current token to be an
// opening curly brace. This acts like an assertion
// because it returns an error if the token is not
// a opening curly brace. It does NOT advance the token.
func (p *parser) openCurlyBrace() error {
if p.Val() != "{" {
return p.SyntaxErr("{")
}
return nil
}
// closeCurlyBrace expects the current token to be
// a closing curly brace. This acts like an assertion
// because it returns an error if the token is not
// a closing curly brace. It does NOT advance the token.
func (p *parser) closeCurlyBrace() error {
if p.Val() != "}" {
return p.SyntaxErr("}")
}
return nil
}
// standardAddress turns the accepted host and port patterns
// into a format accepted by net.Dial.
func standardAddress(str string) (host, port string, err error) {
var schemePort, splitPort string
if strings.HasPrefix(str, "https://") {
schemePort = "https"
str = str[8:]
} else if strings.HasPrefix(str, "http://") {
schemePort = "http"
str = str[7:]
}
host, splitPort, err = net.SplitHostPort(str)
if err != nil {
host, splitPort, err = net.SplitHostPort(str + ":") // tack on empty port
}
if err != nil {
// ¯\_(ツ)_/¯
host = str
}
if splitPort != "" {
port = splitPort
} else {
port = schemePort
}
return
}
type (
// ServerBlock associates tokens with a list of addresses
// and groups tokens by directive name.
ServerBlock struct {
Addresses []Address
Tokens map[string][]token
}
// Address represents a host and port.
Address struct {
Host, Port string
}
)