From c7cb981910fd97128ca5e3f7aa77355a18a56738 Mon Sep 17 00:00:00 2001
From: Francois Kritzinger <francois@codesynthesis.com>
Date: Tue, 10 Dec 2024 16:27:24 +0200
Subject: Handle queued, building notifications

---
 mod/mod-ci-github-post.hxx | 161 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 161 insertions(+)
 create mode 100644 mod/mod-ci-github-post.hxx

(limited to 'mod/mod-ci-github-post.hxx')

diff --git a/mod/mod-ci-github-post.hxx b/mod/mod-ci-github-post.hxx
new file mode 100644
index 0000000..d278ae0
--- /dev/null
+++ b/mod/mod-ci-github-post.hxx
@@ -0,0 +1,161 @@
+// file      : mod/mod-ci-github-post.hxx -*- C++ -*-
+// license   : MIT; see accompanying LICENSE file
+
+#ifndef MOD_MOD_CI_GITHUB_POST_HXX
+#define MOD_MOD_CI_GITHUB_POST_HXX
+
+#include <libbrep/types.hxx>
+#include <libbrep/utility.hxx>
+
+#include <libbutl/curl.hxx>
+
+namespace brep
+{
+  // Send a POST request to the GitHub API endpoint `ep`, parse GitHub's JSON
+  // response into `rs` (only for 200 codes), and return the HTTP status code.
+  //
+  // The endpoint `ep` should not have a leading slash.
+  //
+  // Pass additional HTTP headers in `hdrs`. For example:
+  //
+  //   "HeaderName: header value"
+  //
+  // Throw invalid_argument if unable to parse the response headers,
+  // invalid_json_input (derived from invalid_argument) if unable to parse the
+  // response body, and system_error in other cases.
+  //
+  template <typename T>
+  uint16_t
+  github_post (T& rs,
+               const string& ep,
+               const strings& hdrs,
+               const string& body = "")
+  {
+    using namespace butl;
+
+    // Convert the header values to curl header option/value pairs.
+    //
+    strings hdr_opts;
+
+    for (const string& h: hdrs)
+    {
+      hdr_opts.push_back ("--header");
+      hdr_opts.push_back (h);
+    }
+
+    // Run curl.
+    //
+    try
+    {
+      // Pass --include to print the HTTP status line (followed by the response
+      // headers) so that we can get the response status code.
+      //
+      // Suppress the --fail option which causes curl to exit with status 22
+      // in case of an error HTTP response status code (>= 400) otherwise we
+      // can't get the status code.
+      //
+      // Note that butl::curl also adds --location to make curl follow redirects
+      // (which is recommended by GitHub).
+      //
+      // The API version `2022-11-28` is the only one currently supported. If
+      // the X-GitHub-Api-Version header is not passed this version will be
+      // chosen by default.
+      //
+      fdpipe errp (fdopen_pipe ()); // stderr pipe.
+
+      curl c (path ("-"), // Read input from curl::out.
+              path ("-"), // Write response to curl::in.
+              process::pipe (errp.in.get (), move (errp.out)),
+              curl::post,
+              curl::flags::no_fail,
+              "https://api.github.com/" + ep,
+              "--no-fail", // Don't fail if response status code >= 400.
+              "--include", // Output response headers for status code.
+              "--header", "Accept: application/vnd.github+json",
+              "--header", "X-GitHub-Api-Version: 2022-11-28",
+              move (hdr_opts));
+
+      ifdstream err (move (errp.in));
+
+      // Parse the HTTP response.
+      //
+      uint16_t sc; // Status code.
+      try
+      {
+        // Note: re-open in/out so that they get automatically closed on
+        // exception.
+        //
+        ifdstream in (c.in.release (), fdstream_mode::skip);
+        ofdstream out (c.out.release ());
+
+        // Write request body to out.
+        //
+        if (!body.empty ())
+          out << body;
+        out.close ();
+
+        sc = curl::read_http_status (in).code; // May throw invalid_argument.
+
+        // Parse the response body if the status code is in the 200 range.
+        //
+        if (sc >= 200 && sc < 300)
+        {
+          // Use endpoint name as input name (useful to have it propagated
+          // in exceptions).
+          //
+          json::parser p (in, ep /* name */);
+          rs = T (p);
+        }
+
+        in.close ();
+      }
+      catch (const io_error& e)
+      {
+        // If the process exits with non-zero status, assume the IO error is due
+        // to that and fall through.
+        //
+        if (c.wait ())
+        {
+          throw_generic_error (
+            e.code ().value (),
+            (string ("unable to read curl stdout: ") + e.what ()).c_str ());
+        }
+      }
+      catch (const json::invalid_json_input&)
+      {
+        // If the process exits with non-zero status, assume the JSON error is
+        // due to that and fall through.
+        //
+        if (c.wait ())
+          throw;
+      }
+
+      if (!c.wait ())
+      {
+        string et (err.read_text ());
+        throw_generic_error (EINVAL,
+                             ("non-zero curl exit status: " + et).c_str ());
+      }
+
+      err.close ();
+
+      return sc;
+    }
+    catch (const process_error& e)
+    {
+      throw_generic_error (
+        e.code ().value (),
+        (string ("unable to execute curl:") + e.what ()).c_str ());
+    }
+    catch (const io_error& e)
+    {
+      // Unable to read diagnostics from stderr.
+      //
+      throw_generic_error (
+        e.code ().value (),
+        (string ("unable to read curl stderr : ") + e.what ()).c_str ());
+    }
+  }
+}
+
+#endif // MOD_MOD_CI_GITHUB_POST_HXX
-- 
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