Merge pull request #1098 from lifejwang11/main

add OpenAI json structured example

Author: FluffyKebab

examples/openai-jsonformat-example/README.md

@@ -0,0 +1,22 @@
+# OpenAI STRUCTURED JSON Example
+
+This example demonstrates how to use the OpenAI model with the LangChain Go library to generate structured JSON output.
+
+## What does this example do?
+
+This nifty little program does the following:
+
+1. Sets up a connection to the OpenAI API using the GPT-4o model.
+
+2. Prompts the AI to generate a structured JSON output.
+
+
+## How to Run
+
+1. Make sure you have Go installed on your system.
+2. Set up your OpenAI API key as an environment variable.
+3. Run the program:
+
+```
+go run openai_jsonformat.go
+```

examples/openai-jsonformat-example/go.mod

@@ -0,0 +1,11 @@
+module github.com/tmc/langchaingo/examples/openai-jsonformat-example
+
+go 1.23
+
+require github.com/tmc/langchaingo v0.1.13-pre.0.0.20250106145851-f1fde1f9e4a0
+
+require (
+	github.com/dlclark/regexp2 v1.10.0 // indirect
+	github.com/google/uuid v1.6.0 // indirect
+	github.com/pkoukk/tiktoken-go v0.1.6 // indirect
+)

examples/openai-jsonformat-example/openai-jsonformat.go

@@ -0,0 +1,58 @@
+package main
+
+import (
+	"context"
+	"github.com/tmc/langchaingo/llms"
+	"github.com/tmc/langchaingo/llms/openai"
+	"log"
+)
+
+type User struct {
+	Name string `json:"name"`
+	Age  int    `json:"age"`
+}
+
+func main() {
+	fomat := &openai.ResponseFormat{
+		Type: "json_schema",
+		JSONSchema: &openai.ResponseFormatJSONSchema{
+			Name: "object",
+			Schema: &openai.ResponseFormatJSONSchemaProperty{
+				Type: "object",
+				Properties: map[string]*openai.ResponseFormatJSONSchemaProperty{
+					"name": {
+						Type:        "string",
+						Description: "The name of the user",
+					},
+					"age": {
+						Type:        "integer",
+						Description: "The age of the user",
+					},
+					"role": {
+						Type:        "string",
+						Description: "The role of the user",
+					},
+				},
+				AdditionalProperties: false,
+				Required:             []string{"name", "age", "role"},
+			},
+			Strict: true,
+		},
+	}
+	llm, err := openai.New(openai.WithModel("gpt-4o"), openai.WithResponseFormat(fomat))
+	if err != nil {
+		log.Fatal(err)
+	}
+	ctx := context.Background()
+
+	content := []llms.MessageContent{
+		llms.TextParts(llms.ChatMessageTypeSystem, "You are an expert at structured data extraction. You will be given unstructured text from a research paper and should convert it into the given structure."),
+		llms.TextParts(llms.ChatMessageTypeHuman, "please tell me the most famous people in history"),
+	}
+
+	completion, err := llm.GenerateContent(ctx, content, llms.WithJSONMode())
+	if err != nil {
+		log.Fatal(err)
+	}
+	log.Fatal(completion.Choices[0].Content)
+}