bash/shttpd: a smol shell-based web server

bash/shttpd

@@ -0,0 +1,126 @@
+#!/usr/bin/env bash
+
+declare -A clients http_codes=(
+  [200]=OK [400]="Bad Request" [403]=Forbidden
+  [404]="Not Found" [405]="Method Not Allowed"
+)
+
+enable -f "${SHERVER_SO_PATH-.}"/sherver.so sherver_{bind,select,accept}
+
+if ! sherver-bind -p 8080 -h 0.0.0.0 -v server_fd; then
+  exit
+fi
+
+while true; do
+  if ! sherver-select -iv ready_fds "$server_fd" "${!clients[@]}"; then
+    continue
+  fi
+
+  for fd in "${ready_fds[@]}"; do
+    if (( fd == server_fd )) && sherver-accept -v client_info "$server_fd"; then
+      declare -A __client_{req,resp}_"${client_info[0]}"_ 
+      declare -n client_req=__client_req_${client_info[0]}_
+      client_req[ip]=${client_info[1]}
+      client_req[port]=${client_info[2]}
+      clients[${client_info[0]}]=0
+    else
+      declare -n client_req=__client_req_${fd}_
+      declare -n client_resp=__client_resp_${fd}_
+
+      if ! IFS= read -ru "$fd" line || (( ! ${#line} )); then
+        unset "__client_"{req,resp}"_${fd}_" "clients[$fd]"
+        exec {fd}>&-
+      else
+        (( clients[$fd] += ${#line} + 1 ))
+        line=${line%$'\r'}
+
+        if [[ ! -v client_req[method] ]]; then
+          read -ra req_line <<< "$line"
+          client_req[method]=${req_line[0],,}
+          client_req[req-file]=${req_line[1]}
+          client_req[version]=${req_line[2]-HTTP/1.0}
+
+          case ${client_req[method]} in
+          get)
+            client_resp[has-payload]=yes
+            ;;
+          head)
+            client_resp[has-payload]=no
+            ;;
+          *)
+            client_req[error]=yes
+            client_resp[code]=405
+          esac
+
+          if [[ ${client_req[req-file]} = /* ]]; then
+            client_req[real-file]=.${client_req[req-file]}
+
+            if [[ ${client_req[req-file]} = */ ]]; then
+              client_req[real-file]+=index.html
+            elif [[ -d client_req[real-file] ]]; then
+              client_req[real-file]+=/index.html
+            fi
+          else
+            client_req[error]=yes
+            client_resp[code]=400
+          fi
+
+          if [[ ${client_req[error]} != yes ]]; then
+            if [[ -f ${client_req[real-file]} ]]; then
+              if [[ -r ${client_req[real-file]} ]]; then
+                client_resp[code]=200
+              else
+                client_req[error]=yes
+                client_resp[code]=403
+              fi
+            else
+              client_req[error]=yes
+              client_resp[code]=404
+            fi
+          fi
+        elif [[ $line = *": "* ]]; then
+          hdr_key=${line%%:*} hdr_key=${hdr_key,,}
+          hdr_val=${line#*: } client_req[hdr-$hdr_key]=$hdr_val
+        elif [[ -z $line ]]; then
+          req_host=${client_req[hdr-host]-"$HOSTNAME"}
+          ver=${client_req[version]} code=${client_resp[code]}
+
+          if [[ ${client_req[error]} = yes ]]; then
+            client_req[real-file]=./error.html
+          fi
+
+          payload=$(<"${client_req[real-file]}")
+          client_resp[hdr-Content-Length]=${#payload}
+
+          case ${client_req[req-file]} in
+          *.html)
+            client_resp[hdr-Content-Type]=text/html
+            ;;
+          *.txt)
+            client_resp[hdr-Content-Type]=text/plain
+            ;;
+          *)
+            client_resp[hdr-Content-Type]=application/octet-stream
+          esac
+
+          printf -v 'client_resp[hdr-Date]' '%(%Y-%m-%d %H:%M:%S)T' -1
+          printf '%s %d %s\r\n' "$ver" "$code" "${http_codes[$code]}" >&"$fd"
+
+          for hdr in "${!client_resp[@]}"; do
+            if [[ $hdr = hdr-* ]]; then
+              printf '%s: %s\r\n' "${hdr#hdr-}" "${client_resp[$hdr]}" >&"$fd"
+            fi
+          done
+
+          printf '\r\n' >&"$fd"
+
+          if [[ ${client_resp[has-payload]} = yes ]]; then
+            printf %s "$payload" >&"$fd"
+          fi
+
+          printf '[%s] %s has requested http://%s%s (%s)\n' "${client_resp[hdr-Date]}" "${client_req[ip]}" "$req_host" "${client_req[req-file]}" "${client_req[real-file]}"
+        fi
+      fi
+    fi
+  done
+done