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Commit 213a29a

Browse files
v1 - uncaught exception handling
1 parent 832ae01 commit 213a29a

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5 files changed

+174
-13
lines changed

5 files changed

+174
-13
lines changed

‎api.go‎

Lines changed: 5 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -16,6 +16,7 @@ type API interface {
1616
Put(string, Handler)
1717
Delete(string, Handler)
1818
Exception(string, ErrorHandler)
19+
UncaughtException(ErrorHandler)
1920
ServeHTTP(http.ResponseWriter, *http.Request)
2021
}
2122

@@ -67,6 +68,10 @@ func (a *api) Exception(code string, task ErrorHandler) {
6768
a.list.exception(code, task)
6869
}
6970

71+
func (a *api) UncaughtException(task ErrorHandler) {
72+
a.list.unhandledException(task)
73+
}
74+
7075
func (a *api) ServeHTTP(w http.ResponseWriter, r *http.Request) {
7176
a.handler.serveHTTP(w, r)
7277
}

‎context.go‎

Lines changed: 67 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -1,12 +1,15 @@
11
package rest
22

33
import (
4+
"log"
45
"net/http"
56
)
67

78
type Context interface {
89
Request() *http.Request
10+
Params() map[string]string
911
Status(int) Context
12+
Header(string, string) Context
1013
Throw(string, error)
1114
JSON(interface{})
1215
Raw(interface{})
@@ -16,22 +19,46 @@ type context struct {
1619
w http.ResponseWriter
1720
r *http.Request
1821

19-
// private
20-
end bool
21-
status int
22-
code string
23-
err error
22+
// for internal purpose
23+
params map[string]string
24+
headers map[string]string
25+
end bool
26+
status int
27+
code string
28+
err error
29+
responseProcessed bool
30+
}
31+
32+
func (ctx *context) init() {
33+
ctx.headers = make(map[string]string)
34+
}
35+
36+
func (ctx *context) destroy() {
37+
ctx.w = nil
38+
ctx.r = nil
39+
ctx.headers = nil
40+
ctx.params = nil
41+
ctx.err = nil
2442
}
2543

2644
func (ctx *context) Request() *http.Request {
2745
return ctx.r
2846
}
2947

48+
func (ctx *context) Params() map[string]string {
49+
return ctx.params
50+
}
51+
3052
func (ctx *context) Status(status int) Context {
3153
ctx.status = status
3254
return ctx
3355
}
3456

57+
func (ctx *context) Header(name string, value string) Context {
58+
ctx.headers[name] = value
59+
return ctx
60+
}
61+
3562
func (ctx *context) Throw(code string, err error) {
3663
ctx.code = code
3764
ctx.err = err
@@ -55,6 +82,7 @@ func (ctx *context) Raw(data interface{}) {
5582
func (ctx *context) write(body []byte) {
5683
var err error
5784
ctx.end = true
85+
ctx.responseProcessed = true
5886

5987
if ctx.status > 0 {
6088
ctx.w.WriteHeader(ctx.status)
@@ -65,3 +93,37 @@ func (ctx *context) write(body []byte) {
6593
// TODO: handle error
6694
}
6795
}
96+
97+
// Unhandled Exception
98+
func (ctx *context) unhandledException() {
99+
defer ctx.recover()
100+
101+
if ctx.responseProcessed || ctx.end {
102+
return
103+
}
104+
105+
// NOT FOUND handler
106+
if ctx.code == ErrCodeNotFound {
107+
ctx.Status(http.StatusNotFound)
108+
}
109+
110+
if ctx.err != nil {
111+
ctx.Header("Content-Type", "text/plain;charset=UTF-8")
112+
if ctx.status < 400 {
113+
ctx.Status(http.StatusInternalServerError)
114+
}
115+
ctx.write([]byte(ctx.err.Error()))
116+
}
117+
}
118+
119+
// recover
120+
func (ctx *context) recover() {
121+
err := recover()
122+
if err != nil {
123+
//TODO: debugger mode
124+
log.Printf("runtime error: %v", err)
125+
if !ctx.responseProcessed {
126+
http.Error(ctx.w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
127+
}
128+
}
129+
}

‎examples/uncaught-exception/main.go‎

Lines changed: 34 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,34 @@
1+
package main
2+
3+
import (
4+
"fmt"
5+
"log"
6+
"net/http"
7+
"strconv"
8+
9+
"github.com/go-rs/rest-api-framework"
10+
)
11+
12+
func main() {
13+
var api = rest.New("/")
14+
15+
api.Use(func(ctx rest.Context) {
16+
fmt.Println("/* middleware")
17+
})
18+
19+
api.Get("/page/:id", func(ctx rest.Context) {
20+
// way to reproduce uncaught exception
21+
zero, _ := strconv.ParseInt(ctx.Params()["id"], 10, 32)
22+
x := 10 / zero
23+
ctx.Raw("This will never respond, if value is zero - " + string(x))
24+
})
25+
26+
api.UncaughtException(func(e error, ctx rest.Context) {
27+
log.Println("ERROR: ", e.Error())
28+
//zero, _ := strconv.ParseInt(ctx.Params()["id"], 10, 32)
29+
//_ = 10 / zero
30+
ctx.Raw("Uncaught exception is handled by user")
31+
})
32+
33+
http.ListenAndServe(":8080", api)
34+
}

‎handler.go‎

Lines changed: 60 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -1,6 +1,8 @@
11
package rest
22

33
import (
4+
"errors"
5+
"fmt"
46
"net/http"
57
"strings"
68
)
@@ -9,17 +11,38 @@ type handler struct {
911
list *list
1012
}
1113

14+
// error variables to handle expected errors
15+
var (
16+
ErrCodeNotFound = "URL_NOT_FOUND"
17+
ErrCodeRuntimeError = "RUNTIME_ERROR"
18+
)
19+
1220
func (h *handler) serveHTTP(w http.ResponseWriter, r *http.Request) {
1321
var ctx = &context{
1422
w: w,
1523
r: r,
1624
}
1725

18-
// required "/" to match pattern
19-
var uri = r.RequestURI
20-
if !strings.HasSuffix(uri, sep) {
21-
uri += sep
22-
}
26+
ctx.init()
27+
defer ctx.destroy()
28+
29+
// recovery/handle any runtime error
30+
defer func() {
31+
err := recover()
32+
if err != nil {
33+
if !ctx.end {
34+
defer h.recover(ctx)
35+
ctx.code = ErrCodeRuntimeError
36+
ctx.err = fmt.Errorf("%v", err)
37+
if h.list.uncaughtException != nil {
38+
h.list.uncaughtException(ctx.err, ctx)
39+
} else {
40+
ctx.unhandledException()
41+
}
42+
}
43+
return
44+
}
45+
}()
2346

2447
// on context done, stop execution
2548
go func() {
@@ -30,6 +53,12 @@ func (h *handler) serveHTTP(w http.ResponseWriter, r *http.Request) {
3053
}
3154
}()
3255

56+
// required "/" to match pattern
57+
var uri = r.RequestURI
58+
if !strings.HasSuffix(uri, sep) {
59+
uri += sep
60+
}
61+
3362
// STEP 1: middlewares
3463
for _, handle := range h.list.middlewares {
3564
if ctx.end || ctx.err != nil {
@@ -62,4 +91,30 @@ func (h *handler) serveHTTP(w http.ResponseWriter, r *http.Request) {
6291
handle.task(ctx.err, ctx)
6392
}
6493
}
94+
95+
// STEP 5: unhandled exceptions
96+
if !ctx.end {
97+
// if no error and still not ended that means it NOT FOUND
98+
if ctx.code == "" {
99+
ctx.Throw(ErrCodeNotFound, errors.New("404 page not found"))
100+
}
101+
102+
fmt.Println("this should call...", h.list)
103+
// if user has custom unhandled function, then execute it
104+
if h.list.uncaughtException != nil {
105+
h.list.uncaughtException(ctx.err, ctx)
106+
}
107+
}
108+
109+
// STEP 6: system handle
110+
if !ctx.end {
111+
ctx.unhandledException()
112+
}
113+
}
114+
115+
func (h *handler) recover(ctx *context) {
116+
err := recover()
117+
if err != nil {
118+
ctx.unhandledException()
119+
}
65120
}

‎list.go‎

Lines changed: 8 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -19,9 +19,10 @@ type exception struct {
1919
}
2020

2121
type list struct {
22-
middlewares []middleware
23-
routes []route
24-
exceptions []exception
22+
middlewares []middleware
23+
routes []route
24+
exceptions []exception
25+
uncaughtException ErrorHandler
2526
}
2627

2728
func (l *list) middleware(str string, task Handler) {
@@ -51,3 +52,7 @@ func (l *list) route(method string, str string, task Handler) {
5152
func (l *list) exception(code string, task ErrorHandler) {
5253
l.exceptions = append(l.exceptions, exception{code: code, task: task})
5354
}
55+
56+
func (l *list) unhandledException(task ErrorHandler) {
57+
l.uncaughtException = task
58+
}

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