First commit

1 files changed, 379 insertions, 0 deletions

diff --git a/core/parse/parsing.go b/core/parse/parsing.go
new file mode 100644
index 000000000..6e73bd584
--- /dev/null
+++ b/core/parse/parsing.go
@@ -0,0 +1,379 @@
+package parse
+
+import (
+	"net"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/miekg/dns"
+)
+
+type parser struct {
+	Dispenser
+	block           ServerBlock // current server block being parsed
+	eof             bool        // if we encounter a valid EOF in a hard place
+	checkDirectives bool        // if true, directives must be known
+}
+
+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 := replaceEnvVars(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 != "" { // empty token possible if user typed "" in Caddyfile
+			// 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
+			addr, err := standardAddress(tkn)
+			if err != nil {
+				return err
+			}
+			p.block.Addresses = append(p.block.Addresses, addr)
+		}
+
+		// 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 specified file
+// or globbing pattern. 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 {
+	// syntax check
+	if !p.NextArg() {
+		return p.ArgErr()
+	}
+	importPattern := p.Val()
+	if p.NextArg() {
+		return p.Err("Import takes only one argument (glob pattern or file)")
+	}
+
+	// do glob
+	matches, err := filepath.Glob(importPattern)
+	if err != nil {
+		return p.Errf("Failed to use import pattern %s: %v", importPattern, err)
+	}
+	if len(matches) == 0 {
+		return p.Errf("No files matching import pattern %s", importPattern)
+	}
+
+	// splice out the import directive and its argument (2 tokens total)
+	tokensBefore := p.tokens[:p.cursor-1]
+	tokensAfter := p.tokens[p.cursor+1:]
+
+	// collect all the imported tokens
+	var importedTokens []token
+	for _, importFile := range matches {
+		newTokens, err := p.doSingleImport(importFile)
+		if err != nil {
+			return err
+		}
+		importedTokens = append(importedTokens, newTokens...)
+	}
+
+	// splice the imported tokens in the place of the import statement
+	// and rewind cursor so Next() will land on first imported token
+	p.tokens = append(tokensBefore, append(importedTokens, tokensAfter...)...)
+	p.cursor--
+
+	return nil
+}
+
+// doSingleImport lexes the individual file at importFile and returns
+// its tokens or an error, if any.
+func (p *parser) doSingleImport(importFile string) ([]token, error) {
+	file, err := os.Open(importFile)
+	if err != nil {
+		return nil, p.Errf("Could not import %s: %v", importFile, err)
+	}
+	defer file.Close()
+	importedTokens := allTokens(file)
+
+	// Tack the filename onto these tokens so errors show the imported file's name
+	filename := filepath.Base(importFile)
+	for i := 0; i < len(importedTokens); i++ {
+		importedTokens[i].file = filename
+	}
+
+	return importedTokens, 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 p.checkDirectives {
+		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.tokens[p.cursor].text = replaceEnvVars(p.tokens[p.cursor].text)
+		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 parses an address string into a structured format with separate
+// host, and port portions, as well as the original input string.
+func standardAddress(str string) (address, error) {
+	var err error
+
+	// first check for scheme and strip it off
+	input := str
+
+	// separate host and port
+	host, port, err := net.SplitHostPort(str)
+	if err != nil {
+		host, port, err = net.SplitHostPort(str + ":")
+		// no error check here; return err at end of function
+	}
+
+	// see if we can set port based off scheme
+	if port == "" {
+		port = "53"
+	}
+
+	return address{Original: input, Host: strings.ToLower(dns.Fqdn(host)), Port: port}, err
+}
+
+// replaceEnvVars replaces environment variables that appear in the token
+// and understands both the $UNIX and %WINDOWS% syntaxes.
+func replaceEnvVars(s string) string {
+	s = replaceEnvReferences(s, "{%", "%}")
+	s = replaceEnvReferences(s, "{$", "}")
+	return s
+}
+
+// replaceEnvReferences performs the actual replacement of env variables
+// in s, given the placeholder start and placeholder end strings.
+func replaceEnvReferences(s, refStart, refEnd string) string {
+	index := strings.Index(s, refStart)
+	for index != -1 {
+		endIndex := strings.Index(s, refEnd)
+		if endIndex != -1 {
+			ref := s[index : endIndex+len(refEnd)]
+			s = strings.Replace(s, ref, os.Getenv(ref[len(refStart):len(ref)-len(refEnd)]), -1)
+		} else {
+			return s
+		}
+		index = strings.Index(s, refStart)
+	}
+	return s
+}
+
+type (
+	// ServerBlock associates tokens with a list of addresses
+	// and groups tokens by directive name.
+	ServerBlock struct {
+		Addresses []address
+		Tokens    map[string][]token
+	}
+
+	address struct {
+		Original, Host, Port string
+	}
+)
+
+// HostList converts the list of addresses that are
+// associated with this server block into a slice of
+// strings, where each address is as it was originally
+// read from the input.
+func (sb ServerBlock) HostList() []string {
+	sbHosts := make([]string, len(sb.Addresses))
+	for j, addr := range sb.Addresses {
+		sbHosts[j] = addr.Original
+	}
+	return sbHosts
+}