type Engine struct {
RouterGroup // 路由组
RedirectTrailingSlash bool
RedirectFixedPath bool
HandleMethodNotAllowed bool
ForwardedByClientIP bool
AppEngine bool
UseRawPath bool
UnescapePathValues bool
RemoveExtraSlash bool
RemoteIPHeaders []string
TrustedPlatform string
MaxMultipartMemory int64
// UseH2C enable h2c support.
UseH2C bool
ContextWithFallback bool
delims render.Delims
secureJSONPrefix string
HTMLRender render.HTMLRender
FuncMap template.FuncMap
allNoRoute HandlersChain
allNoMethod HandlersChain
noRoute HandlersChain
noMethod HandlersChain
// 对象池，用来复用gin.Context
pool sync.Pool
// 路由树，根据不同的httpmethod，以及不同的路由，拆分http请求及处理函数
trees methodTrees
maxParams uint16
maxSections uint16
trustedProxies []string
trustedCIDRs []*net.IPNet
}
type RouterGroup struct {
Handlers HandlersChain
basePath string
engine *Engine
root bool
}
type Pool struct {
noCopy noCopy
local unsafe.Pointer // local fixed-size per-P pool, actual type is [P]poolLocal
localSize uintptr // size of the local array
victim unsafe.Pointer // local from previous cycle
victimSize uintptr // size of victims array
// New optionally specifies a function to generate
// a value when Get would otherwise return nil.
// It may not be changed concurrently with calls to Get.
New func() any
}
type methodTree struct {
method string
root *node
}
type methodTrees []methodTree
type node struct {
path string
indices string
wildChild bool
nType nodeType
priority uint32
children []*node // child nodes, at most 1 :param style node at the end of the array
handlers HandlersChain
fullPath string
}
type HandlersChain []HandlerFunc
type methodTree struct {
method string
root *node
}
type methodTrees []methodTree
type node struct {
path string
// 每个 indice 字符对应一个孩子节点路径的首字母
indices string
wildChild bool
nType nodeType
// 后续节点数量
priority uint32
// 孩子节点列表
children []*node // child nodes, at most 1 :param style node at the end of the array
// 处理函数链
handlers HandlersChain
fullPath string
}
type HandlersChain []HandlerFunc
4、注册路由
Go复制代码
func (engine *Engine) addRoute(method, path string, handlers HandlersChain) {
assert1(path[0] == '/', "path must begin with '/'")
assert1(method != "", "HTTP method can not be empty")
assert1(len(handlers) > 0, "there must be at least one handler")
debugPrintRoute(method, path, handlers)
root := engine.trees.get(method)
if root == nil {
root = new(node)
root.fullPath = "/"
engine.trees = append(engine.trees, methodTree{method: method, root: root})
}
root.addRoute(path, handlers)
if paramsCount := countParams(path); paramsCount > engine.maxParams {
engine.maxParams = paramsCount
}
if sectionsCount := countSections(path); sectionsCount > engine.maxSections {
engine.maxSections = sectionsCount
}
}
func (n *node) addRoute(path string, handlers HandlersChain) {
fullPath := path
n.priority++
// Empty tree
if len(n.path) == 0 && len(n.children) == 0 {
n.insertChild(path, fullPath, handlers)
n.nType = root
return
}
parentFullPathIndex := 0
walk:
for {
// Find the longest common prefix.
// This also implies that the common prefix contains no ':' or '*'
// since the existing key can't contain those chars.
i := longestCommonPrefix(path, n.path)
// Split edge
if i < len(n.path) {
child := node{
path: n.path[i:],
wildChild: n.wildChild,
nType: static,
indices: n.indices,
children: n.children,
handlers: n.handlers,
priority: n.priority - 1,
fullPath: n.fullPath,
}
n.children = []*node{&child}
// []byte for proper unicode char conversion, see #65
n.indices = bytesconv.BytesToString([]byte{n.path[i]})
n.path = path[:i]
n.handlers = nil
n.wildChild = false
n.fullPath = fullPath[:parentFullPathIndex+i]
}
// Make new node a child of this node
if i < len(path) {
path = path[i:]
c := path[0]
// '/' after param
if n.nType == param && c == '/' && len(n.children) == 1 {
parentFullPathIndex += len(n.path)
n = n.children[0]
n.priority++
continue walk
}
// Check if a child with the next path byte exists
for i, max := 0, len(n.indices); i < max; i++ {
if c == n.indices[i] {
parentFullPathIndex += len(n.path)
i = n.incrementChildPrio(i)
n = n.children[i]
continue walk
}
}
// Otherwise insert it
if c != ':' && c != '*' && n.nType != catchAll {
// []byte for proper unicode char conversion, see #65
n.indices += bytesconv.BytesToString([]byte{c})
child := &node{
fullPath: fullPath,
}
n.addChild(child)
n.incrementChildPrio(len(n.indices) - 1)
n = child
} else if n.wildChild {
// inserting a wildcard node, need to check if it conflicts with the existing wildcard
n = n.children[len(n.children)-1]
n.priority++
// Check if the wildcard matches
if len(path) >= len(n.path) && n.path == path[:len(n.path)] &&
// Adding a child to a catchAll is not possible
n.nType != catchAll &&
// Check for longer wildcard, e.g. :name and :names
(len(n.path) >= len(path) || path[len(n.path)] == '/') {
continue walk
}
// Wildcard conflict
pathSeg := path
if n.nType != catchAll {
pathSeg = strings.SplitN(pathSeg, "/", 2)[0]
}
prefix := fullPath[:strings.Index(fullPath, pathSeg)] + n.path
panic("'" + pathSeg +
"' in new path '" + fullPath +
"' conflicts with existing wildcard '" + n.path +
"' in existing prefix '" + prefix +
"'")
}
n.insertChild(path, fullPath, handlers)
return
}
// Otherwise add handle to current node
if n.handlers != nil {
panic("handlers are already registered for path '" + fullPath + "'")
}
n.handlers = handlers
n.fullPath = fullPath
return
}
}
5、检索路由
Go复制代码
type nodeValue struct {
handlers HandlersChain
params *Params
tsr bool
fullPath string
}
type skippedNode struct {
path string
node *node
paramsCount int16
}
func (n *node) getValue(path string, params *Params, skippedNodes *[]skippedNode, unescape bool) (value nodeValue) {
var globalParamsCount int16
walk: // Outer loop for walking the tree
for {
prefix := n.path
if len(path) > len(prefix) {
if path[:len(prefix)] == prefix {
path = path[len(prefix):]
// Try all the non-wildcard children first by matching the indices
idxc := path[0]
for i, c := range []byte(n.indices) {
if c == idxc {
// strings.HasPrefix(n.children[len(n.children)-1].path, ":") == n.wildChild
if n.wildChild {
index := len(*skippedNodes)
*skippedNodes = (*skippedNodes)[:index+1]
(*skippedNodes)[index] = skippedNode{
path: prefix + path,
node: &node{
path: n.path,
wildChild: n.wildChild,
nType: n.nType,
priority: n.priority,
children: n.children,
handlers: n.handlers,
fullPath: n.fullPath,
},
paramsCount: globalParamsCount,
}
}
n = n.children[i]
continue walk
}
}
if !n.wildChild {
// If the path at the end of the loop is not equal to '/' and the current node has no child nodes
// the current node needs to roll back to last valid skippedNode
if path != "/" {
for length := len(*skippedNodes); length > 0; length-- {
skippedNode := (*skippedNodes)[length-1]
*skippedNodes = (*skippedNodes)[:length-1]
if strings.HasSuffix(skippedNode.path, path) {
path = skippedNode.path
n = skippedNode.node
if value.params != nil {
*value.params = (*value.params)[:skippedNode.paramsCount]
}
globalParamsCount = skippedNode.paramsCount
continue walk
}
}
}
// Nothing found.
// We can recommend to redirect to the same URL without a
// trailing slash if a leaf exists for that path.
value.tsr = path == "/" && n.handlers != nil
return value
}
// Handle wildcard child, which is always at the end of the array
n = n.children[len(n.children)-1]
globalParamsCount++
switch n.nType {
case param:
// fix truncate the parameter
// tree_test.go line: 204
// Find param end (either '/' or path end)
end := 0
for end < len(path) && path[end] != '/' {
end++
}
// Save param value
if params != nil {
// Preallocate capacity if necessary
if cap(*params) < int(globalParamsCount) {
newParams := make(Params, len(*params), globalParamsCount)
copy(newParams, *params)
*params = newParams
}
if value.params == nil {
value.params = params
}
// Expand slice within preallocated capacity
i := len(*value.params)
*value.params = (*value.params)[:i+1]
val := path[:end]
if unescape {
if v, err := url.QueryUnescape(val); err == nil {
val = v
}
}
(*value.params)[i] = Param{
Key: n.path[1:],
Value: val,
}
}
// we need to go deeper!
if end < len(path) {
if len(n.children) > 0 {
path = path[end:]
n = n.children[0]
continue walk
}
// ... but we can't
value.tsr = len(path) == end+1
return value
}
if value.handlers = n.handlers; value.handlers != nil {
value.fullPath = n.fullPath
return value
}
if len(n.children) == 1 {
// No handle found. Check if a handle for this path + a
// trailing slash exists for TSR recommendation
n = n.children[0]
value.tsr = (n.path == "/" && n.handlers != nil) || (n.path == "" && n.indices == "/")
}
return value
case catchAll:
// Save param value
if params != nil {
// Preallocate capacity if necessary
if cap(*params) < int(globalParamsCount) {
newParams := make(Params, len(*params), globalParamsCount)
copy(newParams, *params)
*params = newParams
}
if value.params == nil {
value.params = params
}
// Expand slice within preallocated capacity
i := len(*value.params)
*value.params = (*value.params)[:i+1]
val := path
if unescape {
if v, err := url.QueryUnescape(path); err == nil {
val = v
}
}
(*value.params)[i] = Param{
Key: n.path[2:],
Value: val,
}
}
value.handlers = n.handlers
value.fullPath = n.fullPath
return value
default:
panic("invalid node type")
}
}
}
if path == prefix {
// If the current path does not equal '/' and the node does not have a registered handle and the most recently matched node has a child node
// the current node needs to roll back to last valid skippedNode
if n.handlers == nil && path != "/" {
for length := len(*skippedNodes); length > 0; length-- {
skippedNode := (*skippedNodes)[length-1]
*skippedNodes = (*skippedNodes)[:length-1]
if strings.HasSuffix(skippedNode.path, path) {
path = skippedNode.path
n = skippedNode.node
if value.params != nil {
*value.params = (*value.params)[:skippedNode.paramsCount]
}
globalParamsCount = skippedNode.paramsCount
continue walk
}
}
// n = latestNode.children[len(latestNode.children)-1]
}
// We should have reached the node containing the handle.
// Check if this node has a handle registered.
if value.handlers = n.handlers; value.handlers != nil {
value.fullPath = n.fullPath
return value
}
// If there is no handle for this route, but this route has a
// wildcard child, there must be a handle for this path with an
// additional trailing slash
if path == "/" && n.wildChild && n.nType != root {
value.tsr = true
return value
}
if path == "/" && n.nType == static {
value.tsr = true
return value
}
// No handle found. Check if a handle for this path + a
// trailing slash exists for trailing slash recommendation
for i, c := range []byte(n.indices) {
if c == '/' {
n = n.children[i]
value.tsr = (len(n.path) == 1 && n.handlers != nil) ||
(n.nType == catchAll && n.children[0].handlers != nil)
return value
}
}
return value
}
// Nothing found. We can recommend to redirect to the same URL with an
// extra trailing slash if a leaf exists for that path
value.tsr = path == "/" ||
(len(prefix) == len(path)+1 && prefix[len(path)] == '/' &&
path == prefix[:len(prefix)-1] && n.handlers != nil)
// roll back to last valid skippedNode
if !value.tsr && path != "/" {
for length := len(*skippedNodes); length > 0; length-- {
skippedNode := (*skippedNodes)[length-1]
*skippedNodes = (*skippedNodes)[:length-1]
if strings.HasSuffix(skippedNode.path, path) {
path = skippedNode.path
n = skippedNode.node
if value.params != nil {
*value.params = (*value.params)[:skippedNode.paramsCount]
}
globalParamsCount = skippedNode.paramsCount
continue walk
}
}
}
return value
}
}
六、gin.Context数据结构
Go复制代码
type Context struct {
writermem responseWriter
Request *http.Request
Writer ResponseWriter
Params Params
handlers HandlersChain
index int8
fullPath string
engine *Engine
params *Params
skippedNodes *[]skippedNode
// This mutex protects Keys map.
mu sync.RWMutex
// Keys is a key/value pair exclusively for the context of each request.
Keys map[string]any
// Errors is a list of errors attached to all the handlers/middlewares who used this context.
Errors errorMsgs
// Accepted defines a list of manually accepted formats for content negotiation.
Accepted []string
// queryCache caches the query result from c.Request.URL.Query().
queryCache url.Values
// formCache caches c.Request.PostForm, which contains the parsed form data from POST, PATCH,
// or PUT body parameters.
formCache url.Values
// SameSite allows a server to define a cookie attribute making it impossible for
// the browser to send this cookie along with cross-site requests.
sameSite http.SameSite
}
