[Platform] Add Perplexity

[welcoMattic]

Q	A
Bug fix?	no
New feature?	yes
Docs?	no
Issues	Fix #...
License	MIT

This PR adds Perplexity as a supported Platform.

Models are: sonar, sonar-pro, sonar-reasoning, sonar-reasoning-pro, and sonar-deep-research

API is similar to OpenAI API, with additional features I will take care of in coming days.

Perplexity docs:

• https://docs.perplexity.ai/api-reference/chat-completions-post
• https://docs.perplexity.ai/guides/streaming
• https://docs.perplexity.ai/guides/search-domain-filters
• https://docs.perplexity.ai/guides/image-guide
• https://docs.perplexity.ai/guides/pdf-uploads

[chr-hertel]

Looks a bit like you started off with an old base branch?

[welcoMattic]

While working on Perplexity specific features integration, I'm wondering how could we handle search_results and citations response keys?

Related Perplexity API reference: https://docs.perplexity.ai/api-reference/chat-completions-post#response-search-results

It's very specific to Perplexity platform, as they perform real web search internally (without leveraging MCP tools).

I see 2 possible solutions:

• Adding a new SearchResult class, extending BaseResult with content, search_results and citations properties.
• Adding a new SearchResultProcessor, implementing OutputProcessorInterface to "store" search_results and citations in Metadata object.

I'd prefer the 1st one.

WDYT @chr-hertel @OskarStark

[chr-hertel]

Let's go with Metadata first and see if there are similar things in other platforms before creating a new kind of result. It is still text right, but they add the search_results and citations to provide some extra information to the text that was generated, right?

[OskarStark]

Yes I would prefer the metadata option too in the first version

[welcoMattic]

It looks like this:

"citations" => array:5 [
    0 => "https://www.esa-gnc.eu/paper?paper_id=23186"
    1 => "http://link.springer.com/10.1007/s11367-017-1261-7"
    2 => "https://www.semanticscholar.org/paper/b11d3453077a784bb5f4b1314b00900d3c177989"
    3 => "https://www.semanticscholar.org/paper/774c12d06cb39fdc4a92433c5148424aa65f62e0"
    4 => "https://www.semanticscholar.org/paper/85dd93d2d37850c7d90d76a0fadd99dc217ed6db"
  ]
  "search_results" => array:5 [
    0 => array:5 [
      "title" => "Evaluating differential GNSS techniques for landing the 1st stage of an RLV – with a skydiver experiment"
      "url" => "https://www.esa-gnc.eu/paper?paper_id=23186"
      "date" => "2023-07-31"
      "last_updated" => null
      "snippet" => ""
    ]
    1 => array:5 [
      "title" => "A perspective for reducing environmental impacts of mussel culture in Algeria"
      "url" => "http://link.springer.com/10.1007/s11367-017-1261-7"
      "date" => "2017-01-27"
      "last_updated" => null
      "snippet" => ""
    ]
    2 => array:5 [
      "title" => "Sterculia urens Roxb. a Promising Gum Secreting Tree Used in Worldwide Food Industries"
      "url" => "https://www.semanticscholar.org/paper/b11d3453077a784bb5f4b1314b00900d3c177989"
      "date" => null
      "last_updated" => null
      "snippet" => ""
    ]
    3 => array:5 [
      "title" => "Sustainable production of microbial polysaccharide xanthan gum from supplemental subststrate."
      "url" => "https://www.semanticscholar.org/paper/774c12d06cb39fdc4a92433c5148424aa65f62e0"
      "date" => null
      "last_updated" => null
      "snippet" => ""
    ]
    4 => array:5 [
      "title" => "28-THE PHYSICAL FITNESS OF A GROUP OF ELDERLY WOMEN"
      "url" => "https://www.semanticscholar.org/paper/85dd93d2d37850c7d90d76a0fadd99dc217ed6db"
      "date" => null
      "last_updated" => null
      "snippet" => ""
    ]
  ]
  "object" => "chat.completion"
  "choices" => array:1 [
    0 => array:4 [
      "index" => 0
      "finish_reason" => "stop"
      "message" => array:2 [
        "role" => "assistant"
        "content" => """
          The search results provided do not contain relevant information about the best French cheese of the first quarter-century of the 21st century.\n
          \n
          Based on general knowledge, determining the "best" French cheese of this period is subjective and depends on criteria such as taste, popularity, awards, and expert opinions. However, some French cheeses have gained international acclaim and continued to be highly regarded in the early 21st century, including:\n
          \n
          - **Comté**: A firm cheese from the Jura region, often praised for its complex nutty and fruity flavors. It has won many awards and is considered one of France’s finest cheeses.\n
          - **Roquefort**: A famous blue cheese made from sheep's milk, known for its strong flavor and creamy texture.\n
          - **Brie de Meaux**: A soft cheese with a rich, buttery taste, often called the "king of cheeses."\n
          - **Époisses**: A washed-rind cheese with a powerful aroma and creamy interior, highly regarded by cheese connoisseurs.\n
          \n
          Cheese competitions such as the World Cheese Awards and guides like the "Guide des Meilleurs Fromages de France" often highlight these cheeses.\n
          \n
          If you are looking for a specific award-winning cheese or expert ranking from the early 21st century, specialized cheese competitions and gastronomic guides would provide the most authoritative information.
          """
      ]
      "delta" => array:2 [
        "role" => "assistant"
        "content" => ""
      ]
    ]
  ]

[OskarStark]

LGTM, but we are lacking tests

[chr-hertel]

From a functional point of view this looks good:

After addressing Oskar's comments we're good to merge here - finally Perplexity - thanks already @welcoMattic!

[welcoMattic]

@OskarStark @chr-hertel comments addressed, tests added, ready for a final review and merge!

[OskarStark]

Just some minor, afterwards good to merge

[OskarStark]

Thanks Mathieu for working on this feature, this is much appreciated.