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Erlang (Key Pair Authentication)

Last updated: 2021-06-01 15:12:07


    This document describes how to authenticate and manage your APIs through key pair authentication in Erlang.


    1. In the API Gateway console, create an API and select the authentication type as "key pair authentication" (for more information, please see API Creation Overview).
    2. Publish the service where the API resides to the release environment (for more information, please see Service Release and Deactivation).
    3. Create a key pair on the key management page in the console.
    4. Create a usage plan on the usage plan page in the console and bind it to the created key pair (for more information, please see Sample Usage Plan).
    5. Bind the usage plan to the API or the service where the API resides.
    6. Generate signing information in Erlang by referring to the Sample Code.


    • The eventually delivered HTTP request contains at least two headers: Date or X-Date and Authorization. More optional headers can be added in the request. If Date is used, the server will not check the time; if X-Date is used, the server will check the time.
    • The value of the Date header is the construction time of the HTTP request in GMT format, such as Fri, 09 Oct 2015 00:00:00 GMT.
    • The value of the X-Date header is the construction time of the HTTP request in GMT format, such as Mon, 19 Mar 2018 12:08:40 GMT. The construction time of the HTTP request cannot deviate from the current time by more than 15 minutes.
    • If it is a microservice API, you need to add two fields in the header: X-NameSpace-Code and X-MicroService-Name. They are not needed for general APIs and are excluded in the demo.

    Sample Code

    %% API
    %% request_api()
    request_api() ->
    %%      Start the inets service. If the project has already started this service, remove this parameter
           Url = "http://service-xxxxxxxx-1234567890.ap-beijing.apigateway.myqcloud.com/release/xxxxx",
          Source = "xxxxxx",
          GMTDate = now_to_utc_string(),
          SecretId = "xxxDf4estwodtdzoke1234567890i3j9jv18wt9u",
          SecretKey = "xxxSNF0CEp3OhN4t91234567890AWrct960X9192",
          Sign = simple_sign(Source, GMTDate, SecretId, SecretKey),
          Header = [
                  {"Source", Source},
                  {"x-Date", GMTDate},
                  {"Authorization", Sign},
                  {"Content-Type", "application/x-www-form-urlencoded"}
           case httpc:request(get, {Url, Header}, [], []) of
                  {ok, {_StatusLine, _Header, Result}} ->
    %% %%                Result -> need decode
                   Error ->
    simple_sign(Source, GMTDate, SecretId, SecretKey) ->
          Auth = "hmac id=\"" ++ SecretId ++ "\", algorithm=\"hmac-sha1\", headers=\"x-date source\", signature=\"",
          SecretKey = "xxxSNF0CEp3OhN4t91234567890AWrct960X9192",
          Source = "xxxxxx",
          SignStr = "x-date: " ++ GMTDate ++ "\n" ++ "source: " ++ Source,
          Mac = crypto:hmac(sha, SecretKey, SignStr),
          Sign = base64:encode(Mac),
          Sign2 = binary_to_list(Sign),
          Sign3 = Auth ++ Sign2 ++ "\"",
    %% Get the current time and convert it into the format of "Mon, 02 Jan 2006 15:04:05 GMT"
    now_to_utc_string() ->
          {{Year, Month, Day}, {Hour, Minute, Second}} = calendar:universal_time(),
          WeekNum = week_num(),
          Month1 = month_to_english(Month),
          WeekNum1 = week_to_english(WeekNum),
          Day1 = lists:flatten(io_lib:format("~2..0w", [Day])),
          Date1 = WeekNum1 ++ ", " ++ Day1 ++ " " ++ Month1,
          Date2 = lists:flatten(
                  io_lib:format(" ~4..0w ~2..0w:~2..0w:~2..0w GMT",
                          [Year, Hour, Minute, Second])),
          Date1 ++ Date2.
    week_num() ->
          {Date, _} = calendar:local_time(),
    %% day_of_the_week
    week_to_english(1) ->
    week_to_english(2) ->
    week_to_english(3) ->
    week_to_english(4) ->
    week_to_english(5) ->
    week_to_english(6) ->
    week_to_english(7) ->
    month_to_english(1) ->
    month_to_english(2) ->
    month_to_english(3) ->
    month_to_english(4) ->
    month_to_english(5) ->
    month_to_english(6) ->
    month_to_english(7) ->
    month_to_english(8) ->
    month_to_english(9) ->
    month_to_english(10) ->
    month_to_english(11) ->
    month_to_english(12) ->
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