WIP: add open router backend

DESCRIPTION

@@ -76,6 +76,7 @@ Collate:
     'provider-github.R'
     'provider-groq.R'
     'provider-ollama.R'
+    'provider-openrouter.R'
     'provider-perplexity.R'
     'provider-snowflake.R'
     'provider-vllm.R'

NAMESPACE

@@ -25,6 +25,7 @@ export(chat_github)
 export(chat_groq)
 export(chat_ollama)
 export(chat_openai)
+export(chat_openrouter)
 export(chat_perplexity)
 export(chat_snowflake)
 export(chat_vllm)

NEWS.md

@@ -1,5 +1,7 @@
 # ellmer (development version)
 
+* `chat_openrouter()` provides support for OpenRouter models (#212)
+
 * `chat_deepseek()` provides support for DeepSeek models (#242)
 
 * `option(ellmer_verbosity)` is no longer supported; instead use the standard httr2 verbosity functions which now support streaming data.

R/provider-openrouter.R

@@ -0,0 +1,157 @@
+#' @include provider-openai.R
+NULL
+
+#' Chat with one of the many models hosted on OpenRouter
+#'
+#' @description
+#' Sign up at <https://openrouter.ai>.
+#'
+#' Support for features depends on the underlying model that you use; see
+#' <https://openrouter.ai/models> for details.
+#'
+#' @export
+#' @family chatbots
+#' @inheritParams chat_openai
+#' @inherit chat_openai return
+#' @examples
+#' \dontrun{
+#' chat <- chat_openrouter()
+#' chat$chat("Tell me three jokes about statisticians")
+#' }
+chat_openrouter <- function(
+  system_prompt = NULL,
+  turns = NULL,
+  api_key = openrouter_key(),
+  model = NULL,
+  seed = NULL,
+  api_args = list(),
+  echo = c("none", "text", "all")
+) {
+  turns <- normalize_turns(turns, system_prompt)
+  model <- set_default(model, "gpt-4o")
+  echo <- check_echo(echo)
+
+  if (is_testing() && is.null(seed)) {
+    seed <- seed %||% 1014
+  }
+
+  provider <- ProviderOpenRouter(
+    base_url = "https://openrouter.ai/api/v1",
+    model = model,
+    seed = seed,
+    extra_args = api_args,
+    api_key = api_key
+  )
+  Chat$new(provider = provider, turns = turns, echo = echo)
+}
+
+chat_openrouter_test <- function(...) {
+  chat_openrouter(..., model = "openai/gpt-4o-mini-2024-07-18")
+}
+
+ProviderOpenRouter <- new_class(
+  "ProviderOpenRouter",
+  parent = ProviderOpenAI,
+)
+
+openrouter_key <- function() {
+  key_get("OPENROUTER_API_KEY")
+}
+
+method(chat_request, ProviderOpenRouter) <- function(
+  provider,
+  stream = TRUE,
+  turns = list(),
+  tools = list(),
+  type = NULL,
+  extra_args = list()
+) {
+  req <- chat_request(
+    super(provider, ProviderOpenAI),
+    stream = stream,
+    turns = turns,
+    tools = tools,
+    type = type,
+    extra_args = extra_args
+  )
+
+  # https://openrouter.ai/docs/api-keys
+  req <- req_headers(
+    req,
+    `HTTP-Referer` = "https://ellmer.tidyverse.org",
+    `X-Title` = "ellmer"
+  )
+
+  req
+}
+
+method(value_turn, ProviderOpenRouter) <- function(provider, result, has_type = FALSE) {
+  # https://openrouter.ai/docs/errors
+  check_openrouter_error(result$error)
+
+  value_turn(
+    super(provider, ProviderOpenAI),
+    result = result,
+    has_type = has_type
+  )
+}
+
+method(stream_parse, ProviderOpenRouter) <- function(provider, event) {
+  if (is.null(event)) {
+    cli::cli_abort("Connection closed unexpectedly")
+  }
+
+  if (identical(event$data, "[DONE]")) {
+    return(NULL)
+  }
+
+  result <- jsonlite::parse_json(event$data)
+  check_openrouter_error(result$error)
+  result
+}
+
+check_openrouter_error <- function(error, call = caller_env()) {
+  if (is.null(error)) {
+    return()
+  }
+  message <- error$message
+  if (is.null(error$metadata$raw$data)) {
+    details <- NULL
+  } else {
+    details <- prettify(error$metadata$raw$data)
+    # don't line wrap
+    details <- gsub(" ", "\u00a0", details, fixed = TRUE)
+  }
+
+  abort(
+    c("message", i = if (!is.null(details)) details),
+    call = call
+  )
+}
+
+method(chat_resp_stream, ProviderOpenRouter) <- function(provider, resp) {
+  repeat({
+    event <- resp_stream_sse(resp)
+    if (is.null(event)) {
+      break
+    }
+
+    # https://openrouter.ai/docs/responses#sse-streaming-comments
+    if (!identical(event$data, character())) {
+      break
+    }
+    Sys.sleep(0.1)
+  })
+
+  event
+}
+
+method(as_json, list(ProviderOpenRouter, ContentText)) <- function(provider, x) {
+  if (identical(x@text, "")) {
+    # Tool call requests can include a Content with empty text,
+    # but it doesn't like it if you send this back
+    NULL
+  } else {
+    list(type = "text", text = x@text)
+  }
+}

R/provider.R

@@ -69,7 +69,7 @@ value_turn <- new_generic("value_turn", "provider")
 as_json <- new_generic("as_json", c("provider", "x"))
 
 method(as_json, list(Provider, class_list)) <- function(provider, x) {
-  lapply(x, as_json, provider = provider)
+  compact(lapply(x, as_json, provider = provider))
 }
 
 method(as_json, list(Provider, ContentJson)) <- function(provider, x) {

R/utils.R

@@ -53,6 +53,13 @@ pretty_json <- function(x) {
   jsonlite::toJSON(x, pretty = TRUE, auto_unbox = TRUE)
 }
 
+prettify <- function(x) {
+  tryCatch(
+    jsonlite::prettify(x),
+    error = function(cnd) x
+  )
+}
+
 check_echo <- function(echo = NULL) {
   if (is.null(echo) || identical(echo, c("none", "text", "all"))) {
     if (env_is_user_facing(parent.frame(2)) && !is_testing()) {

README.Rmd

@@ -47,6 +47,7 @@ ellmer supports a wide variety of model providers:
 * Groq: `chat_groq()`.
 * Ollama: `chat_ollama()`.
 * OpenAI: `chat_openai()`.
+* OpenRouter: `chat_openrouter()`.
 * perplexity.ai: `chat_perplexity()`.
 * Snowflake Cortex: `chat_cortex()`.
 * VLLM: `chat_vllm()`.

README.md

@@ -40,6 +40,7 @@ ellmer supports a wide variety of model providers:
 - Groq: `chat_groq()`.
 - Ollama: `chat_ollama()`.
 - OpenAI: `chat_openai()`.
+- OpenRouter: `chat_openrouter()`.
 - perplexity.ai: `chat_perplexity()`.
 - Snowflake Cortex: `chat_cortex()`.
 - VLLM: `chat_vllm()`.