


The Struggle of Finding a Free Excel to PDF Converter: My Journey and Solution
Jan 12, 2025 pm 04:05 PMMany projects require converting Excel files to PDF format, whether generating reports, sharing data, or creating documents. Initially, I, like many developers, thought this would be an easily automated task. However, the journey to find a free and reliable solution is fraught with challenges: limitations, compatibility issues, and expensive commercial tools.
Eventually, I overcame these difficulties and built my own Excel to PDF converter and made it available as an open source tool to other developers who may face the same dilemma.
Frustrating experience
Business Tools
Initial search results pointed to paid solutions such as Aspose.Cells, Syncfusion and others. While they are powerful, their license fees are high, making them cost-prohibitive for small or personal projects.
Online Services
Free online converters seem to be a good choice, but they are not suitable for automation. These tools often have privacy issues (because files are uploaded to third-party servers), file size limitations, and do not provide programming APIs.
Open Source Library
I also explored open source libraries, but most lacked functionality to convert Excel files to PDF. Even those libraries that do have this feature are often unreliable or don't support modern Microsoft Office formats.
LibreOffice in headless mode
After a few weeks of searching, I stumbled upon a way to use LibreOffice in headless mode. LibreOffice is a free, open-source office suite that can convert multiple file formats, including Excel, to PDF. When running in headless mode, it operates via the command line, making it ideal for automation.
How my solution works
In order to make it easier for developers to use, I built a lightweight Go-based HTTP server that acts as a REST API. This server encapsulates the functionality of LibreOffice and allows any programming language to interact with it via HTTP requests.
Main functions
- Supports multiple file formats: Supports .xlsx, .xls, .csv, .docx, .pptx and other formats.
- Auto Cleanup: Temporary files are automatically deleted after one hour to save disk space.
- Custom Fonts: Custom fonts can be installed by cloning the GitHub repository or using a Docker volume.
- Cross-language integration: Works with any programming language that supports HTTP.
Temporary directory method
Instead of relying on the system's temporary directory, I chose to use a custom ./tmp directory. This ensures consistent behavior since system temporary directories sometimes have unpredictable permissions.
Implementation details
Workflow
-
File upload: The client uses the
/convert
endpoint to upload Excel files through POST requests. - Temporary Storage: The server saves files to the ./tmp directory with file names based on timestamps.
- Convert: Call LibreOffice in headless mode to convert the file to PDF and save the result to the same directory.
- File cleaning: Background goroutine deletes files older than one hour.
- Response: Return the converted PDF as an HTTP response.
Getting Started Guide
GitHub repository
You can find the source code at http://miracleart.cn/link/5b1add8961a1cfa07e60838ffd0f83e7.
Docker image
This project also provides Docker image: wteja/pdf-converter.
Run Docker container
<code>docker pull wteja/pdf-converter docker run -p 5000:5000 wteja/pdf-converter</code>
Examples of integration with other languages
Since the service is exposed over HTTP, you can interact with it using any programming language.
C#
var client = new HttpClient(); var fileContent = new ByteArrayContent(File.ReadAllBytes("example.xlsx")); var formData = new MultipartFormDataContent { { fileContent, "file", "example.xlsx" } }; var response = await client.PostAsync("http://localhost:5000/convert", formData); var pdfBytes = await response.Content.ReadAsByteArrayAsync(); File.WriteAllBytes("output.pdf", pdfBytes);
Node.js
const axios = require("axios"); const FormData = require("form-data"); const fs = require("fs"); const form = new FormData(); form.append("file", fs.createReadStream("example.xlsx")); axios.post("http://localhost:5000/convert", form, { headers: form.getHeaders() }) .then(response => fs.writeFileSync("output.pdf", response.data)) .catch(console.error);
Python
import requests with open("example.xlsx", "rb") as f: response = requests.post("http://localhost:5000/convert", files={"file": f}) with open("output.pdf", "wb") as f: f.write(response.content)
Go
package main import ( "bytes" "io" "mime/multipart" "net/http" "os" ) func main() { file, _ := os.Open("example.xlsx") defer file.Close() body := &bytes.Buffer{} writer := multipart.NewWriter(body) part, _ := writer.CreateFormFile("file", "example.xlsx") io.Copy(part, file) writer.Close() req, _ := http.NewRequest("POST", "http://localhost:5000/convert", body) req.Header.Set("Content-Type", writer.FormDataContentType()) resp, _ := http.DefaultClient.Do(req) defer resp.Body.Close() out, _ := os.Create("output.pdf") defer out.Close() io.Copy(out, resp.Body) }
Challenges and Tradeoffs
Image size
Due to LibreOffice dependencies, the Docker image size is 2.67 GB. Although I tested smaller images such as Alpine, they contained older versions of LibreOffice that were not compatible with modern Microsoft Office formats. Although Debian provides the latest LibreOffice, the generated image is larger (about 3 GB).
Why it’s worth it
The larger image size is an acceptable trade-off compared to the cost of commercial solutions. Once set up, the image can be reused in multiple projects without paying additional license fees.
Conclusion
Frustration in finding a free Excel to PDF converter led me to build my own solution using LibreOffice in headless mode. While it's not perfect, it's free, reliable, and flexible. If you face the same challenge, I hope this project saves you time and effort.
Please check out the project on GitHub or pull the Docker image from Docker Hub. Please let me know how it works for you, or if you have suggestions for improvements.
The above is the detailed content of The Struggle of Finding a Free Excel to PDF Converter: My Journey and Solution. For more information, please follow other related articles on the PHP Chinese website!

Hot AI Tools

Undress AI Tool
Undress images for free

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

Notepad++7.3.1
Easy-to-use and free code editor

SublimeText3 Chinese version
Chinese version, very easy to use

Zend Studio 13.0.1
Powerful PHP integrated development environment

Dreamweaver CS6
Visual web development tools

SublimeText3 Mac version
God-level code editing software (SublimeText3)

Hot Topics

Effective handling of JSON in Go requires attention to structural labels, optional fields and dynamic analysis. Use the struct tag to customize the JSON key name, such as json:"name"; make sure the fields are exported for access by the json package. Use pointers or omitempty tags when processing optional fields to distinguish between unprovided values ??from explicit zeros. When parsing unknown JSON, map[string]interface{} can be used to extract data with type assertions. The default number will be parsed as float64. json.MarshalIndent can be used to beautify the output during debugging, but the production environment should avoid unnecessary formatting. Mastering these techniques can improve the robustness and ability of your code

Go programs can indeed interact with C code through Cgo, which allows Go to call C functions directly. When using Cgo, just import the pseudo-package "C" and embed C code in the comments above the import line, such as including C function definitions and calling them. In addition, external C library can be linked by specifying link flags such as #cgoLDFLAGS. However, there are many issues to pay attention to when using Cgo: 1. Memory management needs to be processed manually and cannot rely on Go garbage collection; 2. Go types may not match C types, and types such as C.int should be used to ensure consistency; 3. Multiple goroutine calls to non-thread-safe C libraries may cause concurrency problems; 4. There is performance overhead for calling C code, and the number of calls across language boundaries should be reduced. Cgo's lack

Yes,Goapplicationscanbecross-compiledfordifferentoperatingsystemsandarchitectures.Todothis,firstsettheGOOSandGOARCHenvironmentvariablestospecifythetargetOSandarchitecture,suchasGOOS=linuxGOARCH=amd64foraLinuxbinaryorGOOS=windowsGOARCH=arm64foraWindow

Go simplifies the use of pointers and improves security. 1. It does not support pointer arithmetic to prevent memory errors; 2. Automatic garbage collection and management of memory without manual allocation or release; 3. The structure method can seamlessly use values ??or pointers, and the syntax is more concise; 4. Default safe pointers to reduce the risk of hanging pointers and memory leakage. These designs make Go easier to use and safer than C/C, but sacrifice some of the underlying control capabilities.

Go compiles the program into a standalone binary by default, the main reason is static linking. 1. Simpler deployment: no additional installation of dependency libraries, can be run directly across Linux distributions; 2. Larger binary size: Including all dependencies causes file size to increase, but can be optimized through building flags or compression tools; 3. Higher predictability and security: avoid risks brought about by changes in external library versions and enhance stability; 4. Limited operation flexibility: cannot hot update of shared libraries, and recompile and deployment are required to fix dependency vulnerabilities. These features make Go suitable for CLI tools, microservices and other scenarios, but trade-offs are needed in environments where storage is restricted or relies on centralized management.

Goensuresmemorysafetywithoutmanualmanagementthroughautomaticgarbagecollection,nopointerarithmetic,safeconcurrency,andruntimechecks.First,Go’sgarbagecollectorautomaticallyreclaimsunusedmemory,preventingleaksanddanglingpointers.Second,itdisallowspointe

To create a buffer channel in Go, just specify the capacity parameters in the make function. The buffer channel allows the sending operation to temporarily store data when there is no receiver, as long as the specified capacity is not exceeded. For example, ch:=make(chanint,10) creates a buffer channel that can store up to 10 integer values; unlike unbuffered channels, data will not be blocked immediately when sending, but the data will be temporarily stored in the buffer until it is taken away by the receiver; when using it, please note: 1. The capacity setting should be reasonable to avoid memory waste or frequent blocking; 2. The buffer needs to prevent memory problems from being accumulated indefinitely in the buffer; 3. The signal can be passed by the chanstruct{} type to save resources; common scenarios include controlling the number of concurrency, producer-consumer models and differentiation

Go is ideal for system programming because it combines the performance of compiled languages ??such as C with the ease of use and security of modern languages. 1. In terms of file and directory operations, Go's os package supports creation, deletion, renaming and checking whether files and directories exist. Use os.ReadFile to read the entire file in one line of code, which is suitable for writing backup scripts or log processing tools; 2. In terms of process management, the exec.Command function of the os/exec package can execute external commands, capture output, set environment variables, redirect input and output flows, and control process life cycles, which are suitable for automation tools and deployment scripts; 3. In terms of network and concurrency, the net package supports TCP/UDP programming, DNS query and original sets.
