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6 changed files with 141 additions and 87 deletions

1
.gitignore vendored
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@ -1,3 +1,2 @@
redis
sus
.env

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@ -1,4 +1,4 @@
FROM golang:1.16
FROM golang:1.18
WORKDIR /go/src/app
COPY . .

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@ -6,10 +6,7 @@ services:
ports: [ "8430:80" ]
environment:
- SECRET=${SECRET}
- MAX_AGE_MS=${MAX_AGE_MS}
restart: unless-stopped
redis:
hostname: sus-redis
image: redis:7
volumes: [ "./redis:/data" ]
restart: unless-stopped
ports: [ "6379:6379" ]

135
main.go
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@ -25,6 +25,7 @@ import (
"net/http"
"os"
"strconv"
"strings"
"time"
"github.com/go-redis/redis/v8"
@ -33,19 +34,17 @@ import (
)
var client = redis.NewClient(&redis.Options{
Addr: "sus-redis:6379",
Addr: "redis:6379",
Password: "",
DB: 0,
})
var SECRET string
var INDEX_GET_REDIRECT = "http://alv.cx"
var MAX_AGE_MS int64 = 500
func main() {
r := mux.NewRouter()
r.HandleFunc("/{shortlink}", shortlinkHandler)
r.HandleFunc("/{shortlink}/", shortlinkHandler)
r.HandleFunc("/", indexHandler)
listenAddress := "0.0.0.0:80"
@ -62,14 +61,6 @@ func main() {
INDEX_GET_REDIRECT = p
}
if p, ok := os.LookupEnv("MAX_AGE_MS"); ok {
if v, err := strconv.ParseInt(p, 10, 64); err != nil {
fmt.Printf("Unable to parse environment variable MAX_AGE_MS: %v\n", p)
} else {
MAX_AGE_MS = v
}
}
log.Fatal(http.ListenAndServe(listenAddress, r))
}
@ -84,30 +75,27 @@ func indexHandler(w http.ResponseWriter, r *http.Request) {
command := r.PostForm.Get("Command")
shortlink := r.PostForm.Get("Shortlink")
value := r.PostForm.Get("Value")
req_timestamp := r.PostForm.Get("Timestamp")
req_timestamp_int, err := strconv.ParseInt(req_timestamp, 10, 64)
if err != nil {
w.WriteHeader(http.StatusBadRequest)
w.Write([]byte("Bad request"))
return
}
redirect := r.PostForm.Get("Redirect")
alt_redirect := r.PostForm.Get("AltRedirect")
alt_condition := r.PostForm.Get("AltCondition")
fmt.Printf("command: %v, shortlink: %v, redirect: %v, alt_redirect: %v, alt_condition: %v\n",
command,
shortlink,
redirect,
alt_redirect,
alt_condition,
)
cur_timestamp := time.Now().UnixNano()
if req_timestamp_int+MAX_AGE_MS*1000*1000 < cur_timestamp {
w.WriteHeader(http.StatusBadRequest)
w.Write([]byte("Bad request"))
return
}
formstring := command + ":" + shortlink + ":" + redirect + ":" + alt_condition + ":" + alt_redirect
fmt.Printf("req_timestamp: %v, command: %v, shortlink: %v, value: %v\n", req_timestamp, command, shortlink, value)
fmt.Println("formstring: " + formstring)
signature := r.Header.Get("Signature")
calculatedSignature := fmt.Sprintf(
"SUS-SIGNATURE-%v",
getSha256HMACSignature(
[]byte(SECRET),
req_timestamp+":"+command+":"+shortlink+":"+value,
command+":"+shortlink+":"+redirect+":"+alt_condition+":"+alt_redirect,
),
)
@ -125,7 +113,21 @@ func indexHandler(w http.ResponseWriter, r *http.Request) {
ctx := context.Background()
_, err := client.Get(ctx, shortlink).Result()
if err == redis.Nil {
err = client.Set(ctx, shortlink, value, 0).Err()
err = client.Set(ctx, shortlink+":redirect", shortlink, 0).Err()
if err != nil {
fmt.Println(err)
w.WriteHeader(500)
w.Write([]byte("500 Internal Server Error"))
return
}
err = client.Set(ctx, shortlink+":altcondition", alt_condition, 0).Err()
if err != nil {
fmt.Println(err)
w.WriteHeader(500)
w.Write([]byte("500 Internal Server Error"))
return
}
err = client.Set(ctx, shortlink+":altredirect", alt_redirect, 0).Err()
if err != nil {
fmt.Println(err)
@ -153,13 +155,16 @@ func indexHandler(w http.ResponseWriter, r *http.Request) {
}
if command == "delete" {
if value != "confirm" {
w.WriteHeader(400)
w.Write([]byte("400 Bad Request"))
}
ctx := context.Background()
if err := client.Del(ctx, shortlink).Err(); err != nil {
if err := client.Del(ctx, shortlink+":redirect").Err(); err != nil {
w.WriteHeader(500)
w.Write([]byte("500 Internal Server Error"))
}
if err := client.Del(ctx, shortlink+":altredirect").Err(); err != nil {
w.WriteHeader(500)
w.Write([]byte("500 Internal Server Error"))
}
if err := client.Del(ctx, shortlink+":altcondition").Err(); err != nil {
w.WriteHeader(500)
w.Write([]byte("500 Internal Server Error"))
}
@ -177,13 +182,13 @@ func indexHandler(w http.ResponseWriter, r *http.Request) {
resp := ""
for _, key := range keys {
value, err = client.Get(ctx, key).Result()
shortlink, err = client.Get(ctx, key).Result()
if err == redis.Nil {
w.WriteHeader(500)
w.Write([]byte("500 Internal Server Error"))
return
}
resp += key + ":" + value + "\n"
resp += key + ":" + shortlink + "\n"
}
w.WriteHeader(200)
@ -196,7 +201,9 @@ func shortlinkHandler(w http.ResponseWriter, r *http.Request) {
fmt.Println("shortlinkHandler called")
shortlink := string(mux.Vars(r)["shortlink"])
ctx := context.Background()
redirect, err := client.Get(ctx, shortlink).Result()
client.Incr(ctx, shortlink + ":hits")
redirect, err := client.Get(ctx, shortlink+":redirect").Result()
fmt.Printf("shortlink: %v, redirect: %v\n", shortlink, redirect)
if err == redis.Nil {
w.WriteHeader(404)
@ -204,13 +211,67 @@ func shortlinkHandler(w http.ResponseWriter, r *http.Request) {
return
} else if err != nil {
fmt.Println(err)
fmt.Println(0)
w.WriteHeader(500)
w.Write([]byte("500 Internal Server Error"))
return
}
altcondition, err := client.Get(ctx, shortlink+":altcondition").Result()
if err == redis.Nil {
http.Redirect(w, r, redirect, 302)
return
} else if err != nil {
fmt.Println(err)
fmt.Println(1)
w.WriteHeader(500)
w.Write([]byte("500 Internal Server Error"))
return
}
altredirect, err := client.Get(ctx, shortlink+":altredirect").Result()
if err == redis.Nil {
http.Redirect(w, r, redirect, 302)
return
} else if err != nil {
fmt.Println(err)
fmt.Println(2)
w.WriteHeader(500)
w.Write([]byte("500 Internal Server Error"))
return
}
altcondition_split := strings.Split(altcondition, ",")
ac_varname := altcondition_split[0]
ac_operator := altcondition_split[1]
ac_required_value, _ := strconv.Atoi(altcondition_split[2])
var ac_varval int
if ac_varname != "timestamp" {
ac_varvalstr, err := client.Get(ctx, shortlink+":"+ac_varname).Result()
if err == redis.Nil {
ac_varval = 0
} else if err != nil {
fmt.Println(err)
fmt.Println(3)
w.WriteHeader(500)
w.Write([]byte("500 Internal Server Error"))
return
} else {
ac_varval, _ = strconv.Atoi(ac_varvalstr)
}
} else {
ac_varval = int(time.Now().Unix())
}
if (ac_operator == "eq" && ac_varval == ac_required_value) ||
(ac_operator == "gt" && ac_varval > ac_required_value) ||
(ac_operator == "lt" && ac_varval < ac_required_value) {
http.Redirect(w, r, altredirect, 307)
} else {
http.Redirect(w, r, redirect, 307)
}
}
func getSha256HMACSignature(secret []byte, data string) string {

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@ -7,11 +7,21 @@ sus URL shortener
- creating a new shortlink at https://pls.cx/shortlink
susmng [-s pls.cx] create -l shortlink -v https://example.com
susmng [-s pls.cx] create -l shortlink -r https://example.com
- creating a new shortlink at https://pls.cx/shortlink which redirects to https://example.com/a the first n times, https://example.com/b any other times
susmng [-s pls.cx] create -l shortlink -r https://example.com/a \
-c hits,gt,<n> -a https://example.com/b
- creating a new shortlink at https://pls.cx/shortlink which redirects to https://example.com/before before unix timestamp n (seconds), https://example.com/after after that
susmng [-s pls.cx] create -l shortlink -r https://example.com/before \
-c timestamp,gt,<n> -a https://example.com/after
- deleting the shortlink https://pls.cx/shortlink
susmng [-s pls.cx] delete -l shortlink -v confirm
susmng [-s pls.cx] delete -l shortlink
- listing all shortlinks on the server pls.cx
@ -33,14 +43,12 @@ flag is not provided.
docker-compose up -d --build
### server environment variables
#### server environment variables
| Variable | Default | Description |
|----------------------|-----------------|----------------------------------------------------------------------------------------|
| `SECRET` | N/A | the secret used for signature verification |
| `LISTEN_ADDRESS` | `0.0.0.0:80` | the address the server is listening on |
| `INDEX_GET_REDIRECT` | `http://alv.cx` | the URL the user should be redirected to if they try to access `/` on the server |
| `MAX_AGE_MS` | 500 | how old a request can be (in milliseconds) before the server will refuse to process it |
- `SECRET`---the secret used for signature verification
- `LISTEN_ADDRESS`---the address the server is listening on (default is `0.0.0.0:80`)
- `INDEX_GET_REDIRECT`---the URL the user should be redirected to if they try to access `/` on the
server (default is `http://alv.cx`)
### setting up susmng

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@ -8,7 +8,6 @@ import pathlib
import os
import json
import sys
import time
def get_args():
@ -19,8 +18,10 @@ def get_args():
parser.add_argument('command')
parser.add_argument('-s', '--server', default="")
parser.add_argument('-l', '--shortlink', default="")
parser.add_argument('-v', '--value', default="")
parser.add_argument('-c', '--config', type=pathlib.Path, default=pathlib.Path(os.path.expanduser('~/.config/susmng/config.json')))
parser.add_argument('-r', '--redirect', default="")
parser.add_argument('-a', '--alt-redirect', default="")
parser.add_argument('-c', '--alt-condition', default="")
parser.add_argument('--config', type=pathlib.Path, default=pathlib.Path(os.path.expanduser('~/.config/susmng/config.json')))
parser.add_argument('-H', '--http', action='store_true')
return parser.parse_args()
@ -49,37 +50,25 @@ def main(args):
secret = config['secrets'][server]
if args.command == "delete" and args.value != "confirm":
print("--value not set to 'confirm'... delete operation may fail")
# accoring to python documentation (https://docs.python.org/3/library/time.html#time.time)
# this function does not explicitly have to use unix time, and implementation is dependent
# platform.
# most platforms (windows, unix) will probably give unix time though.
#
# the server side (main.go file) does explicitly use unix time (time.Now().UnixNano()) to get
# this number, but hopefully there should be no issues on most platforms.
timestamp = str(time.time_ns())
formstring = args.command+":"+args.shortlink+":"+args.redirect+":"+args.alt_condition+":"+args.alt_redirect
print(f"{formstring=}")
r = requests.post(f"{'http' if args.http else 'https'}://{server}",
data = {
'Command': args.command,
'Shortlink': args.shortlink,
'Value': args.value,
'Timestamp': timestamp,
}
'Redirect': args.redirect,
'AltCondition': args.alt_condition,
'AltRedirect': args.alt_redirect,
},
headers = {
'Signature': 'SUS-SIGNATURE-' + hmac.new(
secret.encode("UTF-8"),
(timestamp + ":" + args.command + ":" + args.shortlink + ":" + args.value).encode("UTF-8"),
formstring.encode("UTF-8"),
hashlib.sha256
).hexdigest()
}
print(f"{data=}")
print(f"{headers=}")
r = requests.post(f"{'http' if args.http else 'https'}://{server}", data=data, headers=headers)
)
print(r, file=sys.stderr)
print(r.content.decode().strip())
return 0