erlang - inets httpd：用户指南中的服务器示例不起作用

Question

我直接从 inets 用户指南中复制了代码：

$ erl
Erlang/OTP 19 [erts-8.2] [source] [64-bit] [smp:4:4] [async-threads:10] [hipe] [kernel-poll:false] 

Eshell V8.2  (abort with ^G)

1> inets:start().
ok

2> {ok, Pid} = inets:start(httpd, [{port, 0}, {server_name,"httpd_test"}, {server_root,"/tmp"}, {document_root,"/tmp/htdocs"}, {bind_address, "localhost"}]).

=ERROR REPORT==== 25-Feb-2018::03:08:14 ===
Failed initiating web server: 
undefined
{invalid_option,{non_existing,{document_root,"/tmp/htdocs"}}}

** exception error: no match of right hand side value 
                    {error,
                        {{shutdown,
                             {failed_to_start_child,
                                 {httpd_manager,{127,0,0,1},60152,default},
                                 {error,
                                     {invalid_option,
                                         {non_existing,{document_root,"/tmp/htdocs"}}}}}},
                         {child,undefined,
                             {httpd_instance_sup,{127,0,0,1},60152,default},
                             {httpd_instance_sup,start_link,
                                 [[{port,60152},
                                   {bind_address,{127,0,0,1}},
                                   {server_name,"httpd_test"},
                                   {server_root,"/tmp"},
                                   {document_root,"/tmp/htdocs"}],
                                  15000,
                                  {<0.73.0>,#Port<0.904>},
                                  []]},
                             permanent,infinity,supervisor,
                             [httpd_instance_sup]}}}
3> 

document_root是一个无效的选项？好的，我将检查有效选项列表并更正示例中的错误....嗯，似乎没有。

---

好的，我需要这样做：

$ cd /tmp
$ mkdir htdocs

---

现在，我正在尝试绑定到 localhost 的 ipv6 版本，但我没有运气。httpd 文档说：

{bind_address, ip_address() | hostname() | any}

和 ip_address() 定义为：

ip_address() = {N1,N2,N3,N4} % IPv4 | {K1,K2,K3,K4,K5,K6,K7,K8} % IPv6

但是 N 和 K 没有定义。如果 N 是整数，那么 K 是多少？我试过了：

{bind_address, {0,0,0,0,0,0,0,1}}

但我得到一个错误：

$ erl
Erlang/OTP 19 [erts-8.2] [source] [64-bit] [smp:4:4] [async-threads:10] [hipe] [kernel-poll:false]

Eshell V8.2  (abort with ^G)

1> inets:start().
ok

2> inets:start(httpd, [{port, 0}, {server_name, "httpd_test"}, {server_root, "."}, {document_root, "./htdocs"}, {bind_address,{0,0,0,0,0,0,0,1}}]).
{error,{listen,{exit,badarg}}}

然而，有了 ipv4 地址，一切都按预期工作：

3> inets:start(httpd, [{port, 0}, {server_name, "httpd_test"}, {server_root, "."}, {document_root, "./htdocs"}, {bind_address,{127,0,0,1}}]).
{ok,<0.74.0>}

4> httpd:info(pid(0,74,0)).        
[{mime_types,[{"htm","text/html"},{"html","text/html"}]},
 {server_name,"httpd_test"},
 {bind_address,{127,0,0,1}},
 {server_root,"."},
 {port,63069},
 {document_root,"./htdocs"}]

5> httpc:request("http://localhost:63069/file1.txt").
{ok,{{"HTTP/1.1",200,"OK"},
     [{"date","Mon, 26 Feb 2018 03:02:33 GMT"},
      {"etag","nCZT0114"},
      {"server","inets/6.3.4"},
      {"content-length","14"},
      {"content-type","text/plain"},
      {"last-modified","Mon, 26 Feb 2018 02:51:52 GMT"}],
     "Hello, world!\n"}}

/ets/主机：

##
# Host Database
#
# localhost is used to configure the loopback interface
# when the system is booting.  Do not change this entry.
##
127.0.0.1   localhost
255.255.255.255 broadcasthost
::1             localhost 

接下来，我尝试了{bind_address, any}：

$ erl
Erlang/OTP 19 [erts-8.2] [source] [64-bit] [smp:4:4] [async-threads:10] [hipe] [kernel-poll:false]

Eshell V8.2  (abort with ^G)

1> inets:start().
ok

2> {ok, Server} = inets:start(httpd, [{port, 0}, {server_name, "httpd_test"}, {server_root, "."}, {document_root, "./htdocs"}, {bind_address, any}]).
{ok,<0.72.0>}

3> httpd:info(Server).
[{mime_types,[{"htm","text/html"},{"html","text/html"}]},
 {server_name,"httpd_test"},
 {bind_address,any},
 {server_root,"."},
 {port,63679},
 {document_root,"./htdocs"}]

但是，我无法使用 ipv6 地址执行获取请求：

4> httpc:request("http://[::1]:63679/file1.txt").          
{error,{failed_connect,[{to_address,{"::1",63679}},
                        {inet,[inet],nxdomain}]}}

5> httpc:request("http://127.0.0.1:63679/file1.txt").
{ok,{{"HTTP/1.1",200,"OK"},
     [{"date","Mon, 26 Feb 2018 03:13:35 GMT"},
      {"etag","nCZT0114"},
      {"server","inets/6.3.4"},
      {"content-length","14"},
      {"content-type","text/plain"},
      {"last-modified","Mon, 26 Feb 2018 02:51:52 GMT"}],
     "Hello, world!\n"}}

---

好的，我解决了尝试将服务器绑定到 ipv6 地址时遇到的错误：我需要指定选项{ipfamily, inet6}：

inets:start(httpd, [{port, 0}, 
                    {server_name, "httpd_test"}, 
                    {server_root, "."}, 
                    {document_root, "./htdocs"}, 
                    {ipfamily, inet6}, 
                    {bind_address,{0,0,0,0,0,0,0,1}}]).

但是，我的 httpc:request() 仍然失败：

4> httpd:info(Server).
[{mime_types,[{"htm","text/html"},{"html","text/html"}]},
 {ipfamily,inet6},  
 {server_name,"httpd_test"},
 {bind_address,{0,0,0,0,0,0,0,1}},
 {server_root,"."},
 {port,51284},
 {document_root,"./htdocs"}]

5> httpc:request("http://[::1]:51284/file1.txt").
{error,{failed_connect,[{to_address,{"::1",52489}},
                        {inet,[inet],nxdomain}]}

我可以使用 curl 使用 ipv6 地址发出获取请求：

~$ curl -v "http://[::1]:52489/file1.txt"
*   Trying ::1...
* TCP_NODELAY set
* Connected to ::1 (::1) port 52489 (#0)
> GET /file1.txt HTTP/1.1
> Host: [::1]:52489
> User-Agent: curl/7.58.0
> Accept: */*
> 
< HTTP/1.1 200 OK
< Date: Mon, 26 Feb 2018 05:07:07 GMT
< Server: inets/6.3.4
< Content-Type: text/plain
< Etag: nCZT0114
< Content-Length: 14
< Last-Modified: Mon, 26 Feb 2018 02:51:52 GMT
< 
Hello, world!
* Connection #0 to host ::1 left intact

这让我相信httpc:request()ipv6 地址有问题。

---

好的，我尝试为 ipv6 配置客户端：

1> inets:start().
ok

2> {ok, Client} = inets:start(httpc, [{profile, client1_config}] ). 
{ok,<0.72.0>}

3> Client.
<0.72.0>

7> httpc:set_options([{ipfamily, inet6}], client1_config).    
ok

手指交叉……

8> httpc:request("http://[::1]:52489/file1.txt", client1_config). 
{error,
    {failed_connect,
        [{to_address,{"::1",52489}},
         {inet6,[inet6],nxdomain}]}}

然后我尝试了（我为易读添加了间距）：

9> httpc:request(
         get, 
         "http://[::1]:52489/file1.txt", 
         [], 
         [{ipv6_host_with_brackets, true}], 
         client1_config
   ).
** exception error: no function clause matching httpc:request(get,"http://[::1]:52489/file1.txt",[],
                                                              [{ipv6_host_with_brackets,true}],
                                                              client1_config) (httpc.erl, line 149)

这个错误对我来说毫无意义。httpc:request()有五个 arg 版本，我仔细检查了所有 args 的类型，我的类型是正确的：

httpc:request(atom, string, list_of_tuples, list_of_tuples, atom)

---

好的，第二个参数实际上是一个元组：{string, []}. 这是我现在使用服务器的位置：

7> httpd:info(Server).
[{mime_types,[{"htm","text/html"},{"html","text/html"}]},
 {ipfamily,inet6},
 {server_name,"httpd_test"},
 {bind_address,{0,0,0,0,0,0,0,1}},
 {server_root,"."},
 {port,53686},
 {document_root,"./htdocs"}]

和客户：

32> httpc:get_options(all, client1_config).
{ok,[{proxy,{undefined,[]}},
     {https_proxy,{undefined,[]}},
     {pipeline_timeout,0},
     {max_pipeline_length,2},
     {max_keep_alive_length,5},
     {keep_alive_timeout,120000},
     {max_sessions,2},
     {cookies,disabled},
     {verbose,verbose},
     {ipfamily,inet6},
     {ip,default},
     {port,default},
     {socket_opts,[]}]}

但是我的客户端仍然无法连接到 ipv6 地址。我不知道我是否应该使用 httpc:request() 选项{ipv6_host_with_brackets, true}，所以我一直在尝试两种方式：

34> httpc:request(get, {"http://[::1]:52489/file1.txt", []}, [], [{ipv6_host_with_brackets, true}], client1_config).    
(<0.124.0>) << {dbg,{ok,[{matched,nonode@nohost,1}]}}
(<0.124.0>) << {#Ref<0.0.3.431>,
                {ok,<<16,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0>>}}
(<0.124.0>) << {inet_async,#Port<0.981>,5,{error,econnrefused}}
(<0.124.0>) << {'EXIT',#Port<0.981>,normal}
(<0.124.0>) << {init_error,error_connecting,
                   {#Ref<0.0.3.426>,
                    {error,
                        {failed_connect,
                            [{to_address,{"::1",52489}},
                             {inet6,[inet6],econnrefused}]}}}}
{error,{failed_connect,[{to_address,{"::1",52489}},
                        {inet6,[inet6],econnrefused}]}}

35> httpc:request(get, {"http://[::1]:52489/file1.txt", []}, [], [], client1_config).                               
(<0.126.0>) << {dbg,{ok,[{matched,nonode@nohost,1}]}}
(<0.126.0>) << {#Ref<0.0.3.447>,
                {ok,<<16,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0>>}}
(<0.126.0>) << {inet_async,#Port<0.982>,6,{error,econnrefused}}
(<0.126.0>) << {'EXIT',#Port<0.982>,normal}
(<0.126.0>) << {init_error,error_connecting,
                   {#Ref<0.0.3.442>,
                    {error,
                        {failed_connect,
                            [{to_address,{"::1",52489}},
                             {inet6,[inet6],econnrefused}]}}}}
{error,{failed_connect,[{to_address,{"::1",52489}},
                        {inet6,[inet6],econnrefused}]}}

36> httpc:request(get, {"http://[0:0:0:0:0:0:0:1]:52489/file1.txt", []}, [], [{ipv6_host_with_brackets, true}], client1_config).
(<0.128.0>) << {dbg,{ok,[{matched,nonode@nohost,1}]}}
(<0.128.0>) << {#Ref<0.0.3.463>,
                {ok,<<16,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0>>}}
(<0.128.0>) << {inet_async,#Port<0.983>,7,{error,econnrefused}}
(<0.128.0>) << {'EXIT',#Port<0.983>,normal}
(<0.128.0>) << {init_error,error_connecting,
                   {#Ref<0.0.3.458>,
                    {error,
                        {failed_connect,
                            [{to_address,{"0:0:0:0:0:0:0:1",52489}},
                             {inet6,[inet6],econnrefused}]}}}}
{error,{failed_connect,[{to_address,{"0:0:0:0:0:0:0:1",
                                     52489}},
                        {inet6,[inet6],econnrefused}]}}

37> httpc:request(get, {"http://[0:0:0:0:0:0:0:1]:52489/file1.txt", []}, [], [], client1_config).                       
(<0.130.0>) << {dbg,{ok,[{matched,nonode@nohost,1}]}}
(<0.130.0>) << {#Ref<0.0.3.479>,
                {ok,<<16,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0>>}}
(<0.130.0>) << {inet_async,#Port<0.984>,8,{error,econnrefused}}
(<0.130.0>) << {'EXIT',#Port<0.984>,normal}
(<0.130.0>) << {init_error,error_connecting,
                   {#Ref<0.0.3.474>,
                    {error,
                        {failed_connect,
                            [{to_address,{"0:0:0:0:0:0:0:1",52489}},
                             {inet6,[inet6],econnrefused}]}}}}
{error,{failed_connect,[{to_address,{"0:0:0:0:0:0:0:1",
                                     52489}},
                        {inet6,[inet6],econnrefused}]}}

Answer 1

好的！我让一个客户成功地使用 ipv6 地址发出请求。对于我问题底部的所有请求，我指定了错误的端口。一旦我让客户端端口与服务器端口匹配，那么所有这些请求都会成功。这是我的设置：

服务器配置：

7> httpd:info(Server).
[{mime_types,[{"htm","text/html"},{"html","text/html"}]},
 {ipfamily,inet6},
 {server_name,"httpd_test"},
 {bind_address,{0,0,0,0,0,0,0,1}},
 {server_root,"."},
 {port,53686},
 {document_root,"./htdocs"}]

8>   

客户端配置：

52> httpc:get_options(all, client1_config).
{ok,[{proxy,{undefined,[]}},
     {https_proxy,{undefined,[]}},
     {pipeline_timeout,0},
     {max_pipeline_length,2},
     {max_keep_alive_length,5},
     {keep_alive_timeout,120000},
     {max_sessions,2},
     {cookies,disabled},
     {verbose,false},
     {ipfamily,inet6},  
     {ip,default},
     {port,default},
     {socket_opts,[]}]}

53> 

这是请求的最短语法：

53> httpc:request("http://[::1]:53686/file1.txt", client1_config).
{ok,{{"HTTP/1.1",200,"OK"},
     [{"date","Mon, 26 Feb 2018 10:21:39 GMT"},
      {"etag","nCZT0114"},
      {"server","inets/6.3.4"},
      {"content-length","14"},
      {"content-type","text/plain"},
      {"last-modified","Mon, 26 Feb 2018 02:51:52 GMT"}],
     "Hello, world!\n"}}

所以 httpc:request() 选项{ipv6_host_with_brackets, true}不是必需的。

当我阅读 httpc 文档时，配置文件部分并没有真正向我注册。但是配置文件包含客户端的配置选项，它也是存储 cookie 的位置，因此您需要在后续请求中包含配置文件。

有一个默认配置文件，我猜当您没有指定自己的配置文件时，每个请求都会自动发送该配置文件，我认为默认配置文件会为您处理 cookie。（不，默认情况下不是。我在 httpc:set_options() 的定义下方找到了以下内容：

CookieMode = 启用 | 残疾人| verify
如果启用 cookie，所有有效的 cookie 都会自动保存在客户端管理器的 cookie 数据库中。如果使用选项 verify，则必须调用函数 store_cookies/2 才能保存 cookie。默认为禁用。

您还可以将配置选项添加到默认配置文件。

但是，如果您需要对某些请求而不是其他请求使用像 ipv6 这样的配置，那么您可以创建一个命名配置文件，并在需要时在您的 httpc:request() 和其他请求的默认配置文件中使用命名配置文件（不指定命名配置文件）。有关httpc:set_options()客户端配置选项，请参阅。有点令人困惑的是，httpc:request() 有一个 Options 参数，它允许您指定其他选项（查看 httpc:request/5 定义下方的文档以获取这些选项的列表）。一些请求选项，如同步和流，似乎更适合配置文件：

配置文件跟踪可应用于多个请求的代理选项、cookie 和其他选项。

http://erlang.org/doc/man/httpc.html

如果您通过调用创建配置文件inets:start(httpc, profile_name)，则返回值是客户端的 Pid，它将在单独的进程中分离出来，并在使用该配置文件时处理请求。您可以使用以下任一方法杀死客户端：

inets:stop(httpc, name_of_profile)
inets:stop(httpc, ClientPid)