feat: email multiple recipients

news/changelog-1.9.md

@@ -42,6 +42,7 @@ All changes included in 1.9:
 
 - ([#13882](https://github.com/quarto-dev/quarto-cli/pull/13882)): Add support for multiple email outputs when rendering to `format: email` for Posit Connect.
 - ([#14021](https://github.com/quarto-dev/quarto-cli/issues/14021)): Add `email-version` hook to override detected Connect version when rendering emails for Posit Connect.
+- ([#14098](https://github.com/quarto-dev/quarto-cli/pull/14098)): Add support for dynamic email recipients computed via Python or R code.
 
 ### `html`
 

src/resources/filters/quarto-post/email.lua

@@ -65,6 +65,127 @@ function str_truthy_falsy(str)
   return false
 end
 
+-- Parse recipients from inline code output or plain text
+-- Supports multiple formats:
+--   1. Python list: ['a', 'b'] or ["a", "b"]
+--   2. R vector: "a" "b" "c"
+--   3. Comma-separated: a, b, c
+--   4. Line-separated: a\nb\nc
+-- Returns an empty array if parsing fails
+function parse_recipients(recipient_str)
+  recipient_str = str_trunc_trim(recipient_str, 10000)
+
+  if recipient_str == "" then
+    return {}
+  end
+
+  local recipients = {}
+
+  -- Try Python list format ['...', '...'] or ["...", "..."]
+  if string.match(recipient_str, "^%[") and string.match(recipient_str, "%]$") then
+    local content = string.sub(recipient_str, 2, -2)
+
+    -- Try to parse as Python/R list by splitting on commas
+    -- and stripping quotes and brackets from each item
+    recipients = {}
+    for item in string.gmatch(content, "[^,]+") do
+      local trimmed = str_trunc_trim(item, 1000)
+      -- Strip leading/trailing brackets
+      trimmed = string.gsub(trimmed, "^%[", "")
+      trimmed = string.gsub(trimmed, "%]$", "")
+      trimmed = str_trunc_trim(trimmed, 1000)
+
+      -- Strip leading/trailing quotes (ASCII single/double and UTF-8 curly quotes)
+      -- ASCII single quote '
+      trimmed = string.gsub(trimmed, "^'", "")
+      trimmed = string.gsub(trimmed, "'$", "")
+      -- ASCII double quote "
+      trimmed = string.gsub(trimmed, '^"', "")
+      trimmed = string.gsub(trimmed, '"$', "")
+      -- UTF-8 curly single quotes ' and '  (U+2018, U+2019)
+      trimmed = string.gsub(trimmed, "^" .. string.char(226, 128, 152), "")
+      trimmed = string.gsub(trimmed, string.char(226, 128, 153) .. "$", "")
+      -- UTF-8 curly double quotes " and " (U+201C, U+201D)
+      trimmed = string.gsub(trimmed, "^" .. string.char(226, 128, 156), "")
+      trimmed = string.gsub(trimmed, string.char(226, 128, 157) .. "$", "")
+
+      trimmed = str_trunc_trim(trimmed, 1000)
+      if trimmed ~= "" then
+        table.insert(recipients, trimmed)
+      end
+    end
+    if #recipients > 0 then
+      return recipients
+    end
+  end
+
+  -- Try R-style quoted format (space-separated quoted strings outside of brackets)
+  recipients = {}
+  local found_any = false
+
+  -- Try single quotes: 'a' 'b' 'c'
+  for quoted_pair in string.gmatch(recipient_str, "'([^']*)'") do
+    local trimmed = str_trunc_trim(quoted_pair, 1000)
+    if trimmed ~= "" then
+      table.insert(recipients, trimmed)
+      found_any = true
+    end
+  end
+  if found_any then
+    return recipients
+  end
+
+  -- Try double quotes: "a" "b" "c"
+  recipients = {}
+  for quoted_pair in string.gmatch(recipient_str, '"([^"]*)"') do
+    local trimmed = str_trunc_trim(quoted_pair, 1000)
+    if trimmed ~= "" then
+      table.insert(recipients, trimmed)
+      found_any = true
+    end
+  end
+  if found_any then
+    return recipients
+  end
+
+  -- Try line-separated format (newlines or spaces)
+  -- Check if there are newlines or multiple space-separated emails
+  if string.match(recipient_str, "\n") or
+     (string.match(recipient_str, "@.*%s+.*@") and not string.match(recipient_str, ",")) then
+    recipients = {}
+    -- Split on newlines or spaces
+    for item in string.gmatch(recipient_str, "[^\n%s]+") do
+      local trimmed = str_trunc_trim(item, 1000)
+      if trimmed ~= "" and string.match(trimmed, "@") then
+        table.insert(recipients, trimmed)
+        found_any = true
+      end
+    end
+    if found_any then
+      return recipients
+    end
+  end
+
+  -- Try comma-separated format without quotes
+  -- Split by comma and trim each part
+  recipients = {}
+  found_any = false
+  for part in string.gmatch(recipient_str, "[^,]+") do
+    local trimmed = str_trunc_trim(part, 1000)
+    if trimmed ~= "" and not string.match(trimmed, "^[%[%]]") then
+      table.insert(recipients, trimmed)
+      found_any = true
+    end
+  end
+  if found_any then
+    return recipients
+  end
+
+  -- Could not parse - log warning and return empty
+  quarto.log.warning("Could not parse recipients format: " .. recipient_str)
+  return {}
+end
+
 local html_email_template_1 = [[
 <!DOCTYPE html>
 <html>
@@ -254,6 +375,7 @@ function process_div(div)
       image_tbl = {},
       email_images = {},
       suppress_scheduled_email = nil,  -- nil means not set
+      recipients = {},
       attachments = {}
     }
 
@@ -270,14 +392,50 @@ function process_div(div)
           local email_scheduled_str = str_trunc_trim(string.lower(pandoc.utils.stringify(child)), 10)
           local scheduled_email = str_truthy_falsy(email_scheduled_str)
           current_email.suppress_scheduled_email = not scheduled_email
+        elseif child.classes:includes("recipients") then
+          current_email.recipients = parse_recipients(pandoc.utils.stringify(child))
         else
           table.insert(remaining_content, child)
         end
       else
         table.insert(remaining_content, child)
       end
     end
-
+
+    -- Check for recipients attribute on the email div itself
+    -- This allows referencing metadata set via write_yaml_metadata_block()
+    if div.attributes.recipients then
+      local meta_key = div.attributes.recipients
+      local meta_value = quarto.metadata.get(meta_key)
+
+      if meta_value then
+        -- Convert metadata to recipients array
+        if quarto.utils.type(meta_value) == "List" then
+          local recipients_from_meta = {}
+          for _, item in ipairs(meta_value) do
+            local recipient_str = pandoc.utils.stringify(item)
+            if recipient_str ~= "" then
+              table.insert(recipients_from_meta, recipient_str)
+            end
+          end
+
+          -- If recipients were also found in child divs, merge them
+          if #current_email.recipients > 0 then
+            quarto.log.warning("Recipients found in both attribute and child div. Merging both lists.")
+            for _, recipient in ipairs(recipients_from_meta) do
+              table.insert(current_email.recipients, recipient)
+            end
+          else
+            current_email.recipients = recipients_from_meta
+          end
+        else
+          quarto.log.warning("Recipients metadata '" .. meta_key .. "' is not a list. Expected format: ['[email protected]', '[email protected]']")
+        end
+      else
+        quarto.log.warning("Recipients attribute references metadata key '" .. meta_key .. "' which does not exist.")
+      end
+    end
+
     -- Create a modified div without metadata for processing
     local email_without_metadata = pandoc.Div(remaining_content, div.attr)
 
@@ -508,6 +666,11 @@ function process_document(doc)
       send_report_as_attachment = false
     }
 
+    -- Only add recipients if present
+    if not is_empty_table(email_obj.recipients) then
+      email_json_obj.recipients = email_obj.recipients
+    end
+
     -- Only add images if present
     if not is_empty_table(email_obj.email_images) then
       email_json_obj.images = email_obj.email_images

tests/docs/email/email-recipients-all-patterns-python.qmd

@@ -0,0 +1,125 @@
+---
+title: Email Recipients - All Patterns (Python)
+author: Jules Walzer-Goldfeld
+format:
+    email:
+        email-version: 2
+---
+
+```{python}
+#| echo: false
+import yaml
+from IPython.display import Markdown
+
+def write_yaml_metadata_block(**kwargs):
+    """Write YAML metadata block that will be parsed by Quarto."""
+    yaml_content = yaml.dump(
+        kwargs,
+        default_flow_style=False,
+        allow_unicode=True,
+        sort_keys=False
+    )
+    yaml_block = f"---\n{yaml_content}---\n"
+    return Markdown(yaml_block)
+```
+
+Test document demonstrating all recipient patterns with Python.
+
+```{python}
+# Email 1: Static inline recipients
+static_recipients = ["[email protected]", "[email protected]", "[email protected]"]
+```
+
+::: {.email}
+
+::: {.subject}
+Email 1: Static Inline Recipients
+:::
+
+::: {.recipients}
+`{python} static_recipients`
+:::
+
+::: {.email-text}
+Text version of email with static inline recipients.
+:::
+
+First email with static inline recipients.
+
+:::
+
+```{python}
+# Email 2: Conditional inline recipients
+is_weekday = True  # Fixed value for deterministic testing
+
+if is_weekday:
+    conditional_recipients = ["[email protected]", "[email protected]"]
+else:
+    conditional_recipients = ["[email protected]"]
+```
+
+::: {.email}
+
+::: {.subject}
+Email 2: Conditional Inline Recipients
+:::
+
+::: {.recipients}
+`{python} conditional_recipients`
+:::
+
+::: {.email-text}
+Text version of conditional recipients email.
+:::
+
+Second email with conditional inline recipients.
+
+:::
+
+```{python}
+#| output: asis
+# Email 3: Metadata attribute pattern
+metadata_recipients = ["[email protected]", "[email protected]"]
+write_yaml_metadata_block(metadata_recipients=metadata_recipients)
+```
+
+::: {.email recipients=metadata_recipients}
+
+::: {.subject}
+Email 3: Metadata Attribute Pattern
+:::
+
+::: {.email-text}
+This email uses the metadata attribute pattern.
+:::
+
+Third email using metadata attribute pattern.
+
+:::
+
+```{python}
+#| output: asis
+# Email 4: Conditional metadata attribute pattern
+is_admin = True  # Fixed for testing
+
+if is_admin:
+    admin_recipients = ["[email protected]", "[email protected]"]
+else:
+    admin_recipients = ["[email protected]"]
+
+write_yaml_metadata_block(admin_recipients=admin_recipients)
+```
+
+::: {.email recipients=admin_recipients}
+
+::: {.subject}
+Email 4: Conditional Metadata Attribute
+:::
+
+::: {.email-text}
+This email uses conditional metadata attribute pattern.
+:::
+
+Fourth email using conditional metadata attribute pattern.
+
+:::